MAKERERE
UNIVERSITY
COLLEGE OF ENGINEERING, DESIGN, ART AND TECHNOLOGY SCHOOL OF ENGINEERING DEPARTMENT OF MECHANICAL ENGINEERING
INDUSTRIAL TRAINING REPORT AT DANIEL COMBONI VOCATIONAL INSTITUTE
NAME:
OKELLO JOB LAZARUS
REG. NO. 14/U/1050 STUDENT NO. 214000258
A REPORT SUBMITTED TO MAKERERE UNIVERSITY, DEPARTMENT OF MECHANICAL ENGINEERING IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF THE DEGREE OF BACHELOR OF SCIENCE IN MECHANICAL ENGINEERING OF MAKERERE UNIVERSITY
AUGUST, 2017
DECLARATION
I OKELLO JOB LAZARUS , do declare to the best of my knowledge, that this report is originally mine; it is a true record of the work I undertook during my industrial training at Daniel Comboni Vocational Institute and has never been submitted for the award of the Degree of Bachelor of Science in Mechanical Engineering or any other academic qualification to Makerere University or any other University or academic institution of higher learning.
Signature…………………………
Date……..………….……… Date…….. ………….………
OKELLO JOB LAZARUS
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APPROVAL
This industrial training report was submitted to Makerere University, Department of Mechanical Engineering after the approval of the following:
Signature………………………………… Signature…………………………………
Date….……..…….……… Date….……..…….………
Mr. RACHKARA PHILIP TRAINING SUPERVISOR
Signature………………………………… Signature…………………………………
Date…….……..….. Date…….……..… ..……… ………
Mr. OCHEN RICHARD PRINCIPAL, DANIEL COMBONI VOCATIONAL INSTITUTE
Signature………………………………… Signature…………………………………
Date….……..…….……… Date….……..…….………
Dr. MICHAEL LUBWAMA ACADEMIC SUPERVISOR DEPARTMENT OF MECHANICAL ENGINEERING, MAKERERE UNIVERSITY
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DEDICATION
This report is dedicated to my precious mother, Ms. Florence Auma, who pays the greatest price for my studies. May the ever-good Lord reward you abundantly dearest mum.
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ABSTRACT
Industrial training is one of the requirements for the award of the Degree of Bachelor of Science in Mechanical Engineering of Makerere University. As such, students are required to write and submit reports at the end of the training. This report is the record of what I personally did during my industrial training at Daniel Comboni Vocational Institute (DCVI) from June to August, 2017. It consists of four chapters which altogether explain the objectives of industrial training, entail background information about the institute, various activities carried out at the institute, general overview of Motor Vehicle Technology, the hands-on activities which I took part in and the skills acquired, challenges faced, recommendations and conclusion. Chapter one covers the objectives of industrial training, gives the background information about DCVI including its core values, mission, vision, products and services provided and clientele. Chapter two presents the general overview of Motor Vehicle Technology. Chapter three entails all the practical activities undertaken at the workshop giving for each activity, the different tools and equipment used, technical procedures followed, common faults, their causes and remedies. Chapter four covers the skills acquired, challenges faced, recommendations and conclusion.
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ACKNOWLEDGEMENTS
First and foremost, I express my sincere gratitude to God for His unconditional love, guidance and protection; and for making the training a success. It is entirely by His grace that I have reached this far in life in general and the academic journey in particular. Praise, glory and honor be to Him! I extend my heartfelt gratitude to the management of DCVI for granting me the valuable opportunity to train at their institution. In particular, my appreciation goes to the Principal Mr. Ochen Richard , for admitting me and my training supervisor, Mr. Rachkara Philip for his precious guidance and support rendered to me throughout the training. I also thank all the staff of the DCVI especially those of the MVT Department for the great ideas and thoughts shared with me during the entire training period and for their hospitality and cooperation that made it inevitable for me to acquire the much-desired practical knowledge and skills in the field of Mechanical Engineering. Special thanks also go to the Mechanical Engineering Department of Makerere University and the University Administration at large for availing me with this study time so as to apply the theoretical skills learnt in class into real life problem-solving situations and understanding of the Mechanical Engineering profession at large. With great honor and in a special way, I thank my University supervisor Dr. Michael Lubwama for his tremendous support and guidance rendered to me both during and after the training. Sincere gratitude is also expressed to my fellow trainees- Otim Deogracious, Alega Samuel, Ntambi John Mary , Ngolobe Peter and Anyango Beatrice , with whom we shared valuable ideas; for their support, company and continued team work exhibited during the entire industrial training period. I am immensely grateful to the Chancellor of Gulu Archdiocese Rev. Fr. Martin Agwee for recommending me for internship opportunity at this prominent institution. I am greatly indebted to Uganda’s Assistant Ambassador to Japan, H.E Nyeko Michael Ocula for the critical role he played in securing internship place for me at this prestigious institution. Heartfelt appreciation is also expressed to my Spiritual mother Ms. Elizabeth Diana Babirye for providing the money for printing this internship report and for always being there for me. Special appreciation also goes to Dorcus Nduhukire for typesetting and designing the layout of this report. Most importantly, heartfelt thanks and love are expressed, to my mother Ms. Florence Auma for her tremendous assistance, support, love, encouragement and inspiration, and for paying the greatest price for my education. You are one of a kind and the greatest of all mothers. Finally, to all those who have supported my academic journey yet whose names are not mentioned here, I am truly grateful and very much appreciate all your contributions. May the ever-good Lord immensely reward you all! v
TABLE OF CONTENTS DECLARATION ........................................................................................................................................... i APPROVAL ................................................................................................................................................. ii DEDICATION ............................................................................................................................................. iii ABSTRACT ................................................................................................................................................. iv ACKNOWLEDGEMENTS .......................................................................................................................... v TABLE OF CONTENTS ............................................................................................................................. vi LIST OF TABLES ....................................................................................................................................... xi LIST OF FIGURES .................................................................................................................................... xii LIST OF ACRONYMS USED .................................................................................................................. xiv
CHAPTER ONE: GENERAL INTRODUCTION .................................................................................. 1
1.1 Background ............................................................................................................................................. 1 1.2 Industrial training objectives ................................................................................................................... 1 1.2.1 General objectives ................................................................................................................................ 1 1.2.2 Specific objectives ............................................................................................................................... 1 1.3 Background of Daniel Comboni Vocational Institute ............................................................................. 1 1.3.1 Location of DCVI ................................................................................................................................ 2 1.3.2 Address of DCVI ................................................................................................................................. 2 1.3.3 Mission statement of DCVI ................................................................................................................. 2 1.3.4 Vision statement of DCVI.................................................................................................................... 2 1.3.5 Objectives of DCVI ............................................................................................................................. 2 1.3.6 Services offered by DCVI .................................................................................................................... 3 1.3.7 Clientele of DCVI ................................................................................................................................ 3 vi
1.3.8 Departments at DCVI .......................................................................................................................... 3 1.3.9 The organizational structure of DCVI ................................................................................................. 4 1.3.10 The MVT Department ........................................................................................................................ 6 1.3.11 The Motor Vehicle Workshop ........................................................................................................... 6
CHAPTER TWO: MOTOR VEHICLE TECHNOLOGY .................................. ................ .................................... ................................... ................. 7
2.1 Introduction Introducti on ................................. ................ ................................... ................................... ................................... ................................... ................................... ................................... .................... ... 7 2.2 Vehicle Systems ...................................................................................................................................... 7 2.2.1 The Transmission System .................................................................................................................... 7 2.2.2 The Electrical System .......................................................................................................................... 8 2.2.3 The Fuel System .................................................................................................................................. 9 2.2.4 The Braking System ........................................................................................................................... 10 2.2.5 The Suspension System ..................................................................................................................... 11 2.2.6 The Steering System .......................................................................................................................... 14 2.2.7 The Intake and Exhaust Systems ....................................................................................................... 15
CHAPTER THREE: HANDS-ON ACTIVITIES CARRIED OUT .................................. ................. ................................... .................... 18
3.1 Introduction Introducti on ................................. ................ ................................... ................................... ................................... ................................... ................................... ................................... ................... 18 3.2 Diagnosis and correction of failure of a car battery .............................................................................. 18 3.2.1 Common faults of the car battery, their causes and remedies ............................................................ 18 3.2.2 Fault found with the battery ............................................................................................................... 19 3.2.3 Tools and equipment used to recharge the battery ............................................................................. 20 3.2.4 Technical procedures followed .......................................................................................................... 20 3.3 Replacement of water pump of a Cesspool truck.................................................................................. 20 vii
3.3.1 Common faults with water pumps, their causes and remedies .......................................................... 21 3.3.2 Fault found with the water pump ....................................................................................................... 23 3.3.3 Tools and equipment used to replace the pump ................................................................................. 24 3.3.4Technical procedures followed ........................................................................................................... 24 3.4 Replacement of hydraulic oil of a FAW truck ...................................................................................... 25 3.4.1 Dangers involved in working with hydraulic fluids ........................................................................... 25 3.4.2 Safety precautions when dealing with hydraulic fluids ..................................................................... 26 3.4.3 Common faults with the hydraulic system ......................................................................................... 27 3.4.4 Solutions to the common faults .......................................................................................................... 27 3.4.5 Recommendations on hydraulic systems ........................................................................................... 29 3.4.6 Faults found with the hydraulic oil .................................................................................................... 29 3.4.7 Tools and equipment used to replace the hydraulic oil ...................................................................... 29 3.4.8 Technical procedures followed .......................................................................................................... 29 3.5 Replacement of leaf springs of a FAW truck ........................................................................................ 30 3.5.1 Functions of the suspension of the vehicle ........................................................................................ 31 3.5.2 The purpose of leaf springs ................................................................................................................ 31 3.5.3 Maintenance of leaf springs ............................................................................................................... 31 3.5.4 Fault found with the leaf springs........................................................................................................ 31 3.5.5 Safety precautions while replacing leaf springs ................................................................................. 31 3.5.6 Tools and equipment equi pment used to replace the leaf springs spr ings................................. ................ ................................... ................................... ..................... .... 32 3.5.7 Technical procedures followed to replace the leaf springs ................................................................ 32 3.6 Replacement of a tire of a garbage truck .............................................................................................. 34 3.6.1 Common tire problems and their solutions ........................................................................................ 34 3.6.2 Minimizing tire problems .................................................................................................................. 34 viii
3.6.3 Fault found with the tire ..................................................................................................................... 35 3.6.4 Safety procedures while replacing tires ............................................................................................. 35 3.6.5 Tools and equipment used to replace the tire ..................................................................................... 36 3.6.6 Technical procedures followed .......................................................................................................... 36 3.7 Troubleshooting starter motor of a Toyota Pick-up .............................................................................. 37 3.7.1 Common symptoms of a failing or bad Starter, their causes and remedies ....................................... 37 3.7.2 Safety procedures while troubleshooting a starter motor ................................................................... 38 3.7.3 Tools and equipment used.................................................................................................................. 39 3.7.4 Technical procedures followed .......................................................................................................... 39 3.7.5 Testing the starter ............................................................................................................................... 39 3.8 Adjusting the clutch of a garbage truck ................................................................................................ 40 3.8.1 Common faults with the clutch system, their causes and remedies ................................................... 40 3.8.2 Faults found with the clutch system ................................................................................................... 42 3.8.3Tools and equipment used to adjust the clutch ................................................................................... 43 3.8.4 Technical procedures followed .......................................................................................................... 43 3.9 Panel beating a Pajero Shogun .............................................................................................................. 45 3.9.1Reasons for the operation .................................................................................................................... 45 3.9.2 Tools and equipment used.................................................................................................................. 45 3.9.3 Safety precautions for the operation .................................................................................................. 45 3.9.4 Technical procedures followed .......................................................................................................... 45
CHAPTER FOUR: SKILLS ACQUIRED, CHALLENGES FACED RECOMMENDATIONS AND CONCLUSION ......................................................................................................................................... 48
4.1 Introduction Introducti on ................................. ................ ................................... ................................... ................................... ................................... ................................... ................................... ................... 48 ix
4.2 Experience gained/achievements from the training .............................................................................. 48 4.3 Challenges faced during the training .................................................................................................... 48 4.4 Recommendations ................................................................................................................................. 50 4.5 Conclusion ............................................................................................................................................ 50
REFERENCES .......................................................................................................................................... 51
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LIST OF TABLES
Table 1: DCVI Departments Dep artments and their mandates .................................................... ............................................................................ ........................ 4 Table 2: Water pump troubleshooting chart ................................................................................. 21 Table 3: Clutch diagnosis/troubleshooting chart .............................................................. ............ 41
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LIST OF FIGURES Figure 1: Organizational Structure of DCVI .................................................................................................
5
Figure 2: Organizational Structure of the MVT Department ........................................................................ 6 Figure 3: The Transmission System ..............................................................................................................
7
Figure 4: The Electrical System ....................................................................................................................
8
Figure 5: The Fuel System ..........................................................................................................................
10
Figure 6: The Braking System ....................................................................................................................
11
Figure 7: The Suspension System ...............................................................................................................
12
Figure 8: The Front Suspension System .....................................................................................................
13
Figure 9: The Rear Suspension System ......................................................................................................
14
Figure 10: The Steering System ..................................................................................................................
15
Figure 11: The Intake System .....................................................................................................................
16
Figure 12: The Exhaust System ..................................................................................................................
17
Figure 13: Recharging the battery ............................................................................................................... 20 Figure 14: The removed water pump ..........................................................................................................
24
Figure 15: The unit that houses the water pump ......................................................................................... 25 Figure 16: Draining the hydraulic oil .......................................................................................................... 30 Figure 17: Removing the broken leaf springs .............................................................................................
33
Figure 18: The broken leaf springs that were removed ...............................................................................
33
Figure 19: Removing the tire ......................................................................................................................
37
Figure 20: Testing the voltage being received by the starter ...................................................................... 39 Figure 21: The opened clutch system .........................................................................................................
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44
Figure 22: The removed pressure and clutch plates .................................................................................... 44 Figure 23: Sanding using smooth sand paper 500 ......................................................................................
47
Figure 24: Covering the parts that were not supposed to be sprayed ................ ................. .................. ....... 47
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LIST OF ACRONYMS USED
ABS
Antilock Brake System
AC
Alternating Current
BCP
Building & Concrete Practice
BOG
Board of Governors
C&J
Carpentry & Joinery
DCVI
Daniel Comboni Vocational Institute
DIT
Directorate of Industrial Training
E.I
Electrical Installation
EU
European Union
Fr
Father
H.E
His Excellency
km
Kilometer
kpa
kilopascal
MECP
Mechanical Engineering Craft Practices
MoE&S
Ministry of Education and Sports
MVT
Motor Vehicle Technology
NEMA
National Environment Management Authority
NGOs
Non-Governmental Organizations
NOA
Non-Asbestos
P.O
Post Office
PPE
Personal Protective Equipment
RD
Road
REG. NO.
Registration Number
Rev
Reverend
STUDENT. NO.
Student Number
UBTEB
Uganda Business & Technical Examinations Board
UPDF
Uganda People’s Defense Forces
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CHAPTER ONE: GENERAL INTRODUCTION 1.1 Background
Industrial attachment is an industrial based practical training experience that prepares students for the tasks they are expected to perform on completion of their training.
1.2 Industrial training objectives
The university through its industrial training program aims at achieving a number of objectives and these include the following; 1.2.1 General objectives
To produce practical oriented graduates that meet the required job-related competences of their future employers. To serve as a go-between the University and the various partners who consume services and/or products of the University. 1.2.2 Specific objectives
To enable students get hands-on experience in real-life situations they are expected to work in when they graduate. To provide an opportunity for students to apply the principles and techniques theoretically learnt into real-life problem-solving situations. To provide an opportunity for students and academic staff to interact with stakeholders and potential employers to appreciate industrial situations that will also generate information for curricula review and improvement. To develop an understanding of work ethics, employment demands, responsibilities and opportunities. To enable students to bridge the gap between the theories studied in class and the practical part of the theory. 1.3 Background of Daniel Comboni Vocational Institute
Daniel Comboni Vocational Institute (DCVI) is a mixed day school with limited accommodation facilities for students. It was founded in 1995 by the Comboni Missionaries as a private institution, in line with the government policies and academic directives of the Ministry of Education and Sports (MoE&S). DCVI was started in response to the needs of the local population. In spite of the troubles and insecurity at the time, it was hoped that the Institute would be a tremendous contribution to the local population’s hopes and legitimate aspirations to 1
peace. The Institute aspires and hopes to provide provid e advanced Vocational skills and knowledge to technicians and craftsmen / women to meet the growing demands for skilled workers in the public and private sectors, which is a good tool to fight poverty, hunger and neglect. It is a registered institution and is a centre for Uganda Business & Technical Ex aminations Board (UBTEB) and Directorate of Industrial Training (DIT) of the Ministry of Education and Sports. DCVI offers five courses of two years each leading to the award of National, craft and Advanced certificates. They are: Motor Vehicle Technology (MVT), Electrical Installation (E.I), Carpentry & Joinery (C&J), Building and Concrete Practice (BCP) and Mechanical Engineering Craft Practices (MECP). 1.3.1 Location of DCVI
DCVI is located in Layibi village, Techo parish, Layibi Division, Gulu Municipality on plot 61/95 Daniel Comboni Road, 600m off Juba Road. 1.3.2 Address of DCVI
P.O.BOX, 777 Gulu-Uganda. Tel: +256-392 799 606 Fax: +256-471 432 827 Email: Website:
[email protected] [email protected] g www.combonivocational.ac.ug
1.3.3 Mission statement of DCVI
To provide advanced skills and knowledge to technicians and craftsmen and women to meet the growing demands for skilled workers in both the public and private sectors.
1.3.4 Vision statement of DCVI
Promotion of skill-based training for self-employment.
1.3.5 Objectives of DCVI
To provide technical training so as to create competent craftsmen/women and technicians. To provide scientific, mathematical and humanitarian foundation to enable students competently handle the technical aspects of their trades.
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To create self-reliant citizens thus becoming job creators and not job seekers. To allow young Ugandans of different religions acquire training and professional knowledge in the available technical trades. To equip students with communication skills that facilitates effective knowledge sharing and transfer. To make students responsible and conscious of their roles in creating and developing the Christian society. 1.3.6 Services offered by DCVI
The services are provided via the Production unit. The institute, through the Production unit, which is made up of all the departments, provides services such as Repair of Customers' Vehicles, fabrication of metal products such as doors and windows gates, among others, making of furniture out of timber for customers, Construction of buildings, Electrical Wiring and Repair of electric motors and generators among others. Other services in the related fields are also available.
1.3.7 Clientele of DCVI
The clientele of DCVI include among others; the general public, Toyota Gulu, Gulu Archdiocese institutions, the government of the Republic of Uganda, politicians, schools, hotels, business entities, Government ministries, mobile service providers and telecommunication companies, UMEME, Bank of Uganda and all other financial institutions operating within Gulu and neighboring areas, Non-Governmental Organizations (NGOs) operating within Gulu and neighboring areas, Tourists, Health centers and hospitals, Security institutions like the UPDF, Uganda Police, Uganda Prison and many others. 1.3.8 Departments at DCVI
DCVI is made up of five Departments which altogether form the Production Unit, through which the services of the institution are provided to its clientele. The departments and their respective mandates are presented in Table 1 below.
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Table 1: DCVI Departments and their mandates DEPARTMENT MANDATE Mechanical Engineering Craft Responsible for machining works using lathe, milling, grinding, drilling, Practices hydraulic press, and shaping machines, welding and fabrication works, and (MECP) roofing among others: both within and outside the institute.
Carpentry and Joinery Deals in furniture like chairs, tables, doors, door frames, cupbo ards, wooden (C&J) beds, windows and window frames among others. Building and Concrete Practice (BCP)
Motor Vehicle Technology (MVT) Electrical Installation (E.I)
Deals in general building and construction works and construction materials like cement and bricks among others. o thers.
Responsible for maintenance of automobiles and eq uipment like vehicles, graders, rollers, tractors, caterpillars among others and general automotive works. Electrical installation works, repair and maintenance of electrical appliances like radios, screens, phones, cameras, refrigerators and others, solar installation works, motor rewinding and servicing, transformer rewinding and servicing, and general electrical works both within and outside the institute.
1.3.9 The organizational structure of DCVI
The institute has a Board of Governors (BOG) which meets regularly on policy issues, reviews narrative and financial reports from the Institute’s Institute’s Administration and approves yearly budget. The Administration is headed by the Director and the Deputy Director and the Personnel Coordinator. The three officers form the Management Committee; other members of staff in the Administration include the Financial Assistant, Accountant, two Secretaries, Cashier and Office Assistant. In the training area, each trade has a Head of Department; these include MECP, E.I, MVT, C&J and BCP Departments. Each of the above departments has teachers and support staff. The list of teachers also includes part-time teachers for general subjects such as Entrepreneurship and English. Production Units as 4
well have their Heads of Departments and support staff. The above set-up constitutes the whole team of the work force in DCVI. The organizational structure of DCVI is as shown in Figure 1 below. During my internship, I was assigned to the MVT Department which is under the Production Unit together with the other Departments. A description of the activities carried out in this Department is given in section 1.3.10 of this report. BOARD OF GOVERNORS
DIRECTOR
MANAGEMENT COMMITTEE
DEPUTY DIRECTOR
HEADS OF TRAINING DEPARTMENTS
PERSONNEL COODINATOR
FINANCIAL ASSISTANT
EXAMINATIONS SECRETARY
TEACHERS SECRETARY PRODUCTION UNITS
ACCOUNTANT
STORE
SUPPORT SUPPORT STAFF APPRENCTICE STUDENTS
CASHIER
SUPPORT STAFF DRIVER SECURITY
KITCHEN STAFF
Figure 1: Organizational Structure of DCVI
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1.3.10 The MVT Department
The Department is responsible for maintenance of automobiles and equipment like vehicles, graders, rollers, tractors, caterpillars among others and general automotive works. At DCVI, interns are attached to the different Departments on the basis of the respective courses they pursue. The Departments then design training programs for them. Mechanical Engineering interns are attached to the MVT and/or MECP Departments. As such, I was attached to the MVT Department. Its organizational structure is shown in Figure 2 below.
Head of Department
Motor Vehicle Technicians
Support Staff Figure 2: Organizational Structure of the MVT Department 1.3.11 The Motor Vehicle Workshop
This is the referral workshop for all auto-mobiles of DCVI and Gulu Archdiocese institutions. Vehicles and equipment from Gulu Municipality and neighboring areas are also serviced here. It is thus responsible for maintaining and ensuring that they are all in good mechanical and electrical working conditions. It is located within the institute. A number of activities are carried out in this workshop with an aim of keeping the motor vehicles and equipment in good operating conditions. Some of these activities include; Engine overhaul, gear box overhaul, auto-body repair, general servicing and minor repairs among others. All the activities are carried out by experienced auto-mechanics and electricians who are wellversed with the motor vehicle internal and external systems. The fleet of the workshop consists of tractors, construction equipment, service vehicles, managerial vehicles and Executive vehicles. They total up to approximately 220 in number. While training at the workshop, I engaged in very many activities as exhaustively explained in chapter three.
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CHAPTER TWO: MOTOR VEHICLE TECHNOLOGY 2.1 Introduction
A motor vehicle is a self-propelled road vehicle or off-road vehicle, vehicle, commonly wheeled, wheeled, that does not operate on rails, on rails, such such as trains as trains or trams trams and used for the transportation of passengers, or passengers and property. The vehicle propulsion is provided by an an engine or motor, usually by an internal combustion engine, engine, or an electric motor, motor, or some combination of the two, such as hybrid electric vehicles and plug-in and plug-in hybrids. 2.2 Vehicle Systems
An automobile is the result of combined work of a number of systems. Each system, though primarily independent, is influenced by the effect of other systems interacting with it. The different systems are given below. 2.2.1 The Transmission System
Transmission system in a car helps to transmit mechanical power from the car engine to give kinetic energy to the wheels. It is an interconnected system of gears, shafts, and other electrical gadgets that form a bridge to transfer power and energy from the engine to the wheels. The complete set up of the system, shown in Figure 3 below, helps to maintain the cruising speed of the car without any disturbance to the car’s performance.
Figure 3: The Transmission System Link to the image: (http://usciencecompendium.blogspot.com/2014/12/automobile-transmission-system part-1.html) 7
2.2.2 The Electrical System The electrical system, shown in Figure 4 below, consists of the battery, starter and alternator. The battery provides juice to the starter. Then, the alternator gives that battery the energy it needs to power the car. If one of these parts is not working properly, properly, the car won’t start or run correctly.
a Battery Until your vehicle starts, the battery provides the car’s entire electrical current. This includes the current to the ignition and fuel systems, which are responsible for creating the combustion necessary for the engine to function. b Starter While the battery supplies the power to start the vehicle, the starter is really what gets the engine going. The battery supplies a small amount of power to the starter motor. The starter then rotates the f lywheel, lywheel, which turns the crankshaft and begins the movement of the engine’s pistons. This intricate process is why it’s key key to make sure the starter starter works. c Alternator When the engine is running, the alternator keeps the battery charged and the electrical system going. The car can start with a faulty alternator, but it won’t be able to run for an extended period of time. If the alternator requires replacement, the vehicle’s electrical system will perform erratically, its battery will discharge, and eventually the engine will lose power.
Figure 4: The Electrical System Link to the image: (https://repairpal.com/electrical-lights)
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2.2.3 The Fuel System All internal combustion engines need three things to run:-Air, Fuel and Spark. The fuel system is critical in storing and delivering the gasoline or diesel fuel the engine needs to run. The fuel system has the following components:-fuel pump, fuel lines and filter as shown in Figure 5 below. A failure in any of these fuel system components has devastating effects on the car.
a Fuel tank This is basically a holding tank for the fuel. When you fill up at a gas station, the gas travels down the filler tube and into the tank. In the tank there is a sending unit which tells the gas gauge how much gas is in the tank. In recent years the gas tank has become a little more complicated, as it now often houses the fuel pump and has more emissions controls to prevent vapors leaking into the air. b Fuel pump On newer cars the fuel pump is usually installed in the fuel tank. Older cars have the fuel pump attached to the engine or on the frame rail between the tank and the engine. If the pump is in the tank or on the frame rail, then it is electric and is run by the car ’s battery. Fuel pumps mounted to the engine use the motion of the engine to pump the fuel, most often being driven by the camshaft, but sometimes the crankshaft. c Fuel filter Clean fuel is critical to engine life and performance. Fuel injectors and carburetors have tiny openings which clog easily so filtering the fuel is a necessity. Filters can be before or after the fuel pump, sometimes both. They are most often made from a paper element, but can be stainless steel or synthetic material and are designed to be disposable in most cases. Some performance fuel filters will have a washable mesh, which eliminates the need for replacement. d Fuel injectors The fuel injector is basically a tiny electric valve which opens and closes with an electric signal. By injecting the fuel close to the cylinder head, the fuel stays atomized (in tiny particles) so it will burn better when ignited by the spark plug. e Carburetors A carburetor takes the fuel and mixes mix es it with air. While simple in operation, they tend to need frequent tuning and rebuilding. This is why n ewer cars have done away with carburetors in favor of fuel injection
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Figure 5: The Fuel System Link to the image: (http://www.xpertechautorepair.com/fuel_injection.html) 2.2.4 The Braking System
The Vehicle’ Vehicle’s braking system, shown in Figure 6 below, is designed to perform only one job and that is to safely stop the vehicle. In order to achieve that, there are three key things needed:a vehicle operator, hydraulic pressure and friction. When the vehicle operator pushes the brake pedal down, the pedal p edal levers and rods actuate the power po wer brake booster. The booster uses engine vacuum or a pump to multiply the force from the operator’s operator’s foot to the master cylinder. Hydraulic lines connected to the master cylinder c ylinder go out to a proportioning valve or to the ABS (Antilock Brake System) module then to each either brake caliper if the vehicle has disc brakes or to wheel cylinder if it has drum brakes. The brake fluid in the lines flows into the calipers or wheel cylinders and the hydraulic pressure pushes the brake pads against the rotors of brake shoes against the drums causing friction which stops the vehicle. a
Disc Brakes
A disk brake system consists of a brake disk, a brake caliper and brake pads. When the brake pedal is applied, pressurized hydraulic brake fluid squeezes the brake pad friction material against the surface of the rotating brake disc. The result of this contact produces friction which enables the vehicle to slow down or stop.
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b
Drum brakes
A drum brake system consists of hydraulic wheel cylinders, brake shoes and a brake drum. When the brake pedal is applied the two curved brake shoes, which have a friction material lining, are forced by hydraulic wheel cylinders against the inner surface of a rotation brake drum. The result of this contact produces frictions which enables the vehicle to slow down or stop.
Figure 6: The Braking System Link to the image: (https://www.pinterest.com/pin/360076932694018134/)
2.2.5 The Suspension System
Suspension is the system of tires, tire air, springs, shock absorbers and linkages that connects a vehicle to its wheels and allows relative motion between the two. Suspension systems serve a dual purpose:-contributing to the vehicle's road-holding/handling and braking for good active safety and driving pleasure, and keeping vehicle occupants comfortable and reasonably well isolated from road noise, noise, bumps, and vibrations. The suspension also protects the vehicle itself and any cargo or luggage from damage and wear. The design of front and rear suspension of a car may be different. The suspension system of the motor vehicle, shown in Figure 7 below, is divided into front suspension and rear suspension.
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Figure 7: The Suspension System Link to the image: (http://www.avgnewton.com/suspension.html) a
The Front Suspension System
The purpose of the front suspension is to support the weight of the vehicle. Automobiles commonly use independent front suspension whereby if one of the tires moves over a bump, the other will not be affected. The front suspension, shown in Figure 8 below, is mainly composed of the following; ball joints, control arms, shaft bushings, coil springs, stabilizers, shock absorbers, steering knuckle and spindle.
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Figure 8: The Front Suspension System Link to the image: (http://eramandeepbansal.blogspot.ug/2013/08/front-wheel-suspensionsystem.html) b
The Rear Suspension System
The rear suspension system is designed to keep the rear axle and the wheels in their proper position under the car body. The rear suspension suspen sion allows, shown in Figure 9 below, each of the rear wheels to move up and down independent of the frame so as to maintain alignment and good vehicle control. The main components include leaf springs which are used to dampen noise and vibrations from the road to the frame of the vehicle, and shock absorbers which are hydraulic device that help to control the up, down and rolling of the car body
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Figure 9: The Rear Suspension System Link to the image: (http://arrc.ebscohost.com/ebsco_static/repairtips/8852CH23_Rear_Suspensions.htm) 2.2.6 The Steering System
The steering The steering system, shown in Figure 10 below, converts the rotation of the steering wheel into a swiveling movement of the road wheels in such a way that the steering-wheel rim turns a long way to move the road wheels a short way. There are two steering systems in common use - the rack and pinion and the steering box. On large cars, either system may be power assisted to reduce further the effort needed to move it, especially when the car is moving slowly.
a
The rack-and-pinion system
At the base of the steering column there is a small pinion (gear wheel) inside a housing. Its teeth mesh with a straight row of teeth on a rack - a long transverse bar. Turning the pinion makes the rack move from side to side. The ends of the rack are coupled to the road wheels by track rods. This system is simple, with few moving parts to become worn or displaced, so its action is precise. A universal joint in the steering column allows it to connect with the rack without angling the steering wheel awkwardly sideways.
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b
The steering-box system
At the base of the steering column there is a worm gear inside a box. A worm is a threaded cylinder like a short bolt. Imagine turning a bolt which holding a nut on it; the nut would move along the bolt. In the same way, turning the worm moves anything fitted into its thread. Depending on the design, the moving part may be a sector (like a slice of a gear wheel), a peg or a roller connected to a fork, or a large nut. The nut system has hardened balls running inside the thread between the worm and the nut. As the nut moves, the balls roll out into a tube that takes them back to the start; it is called a recirculating-ball system. The worm moves a drop arm linked by a track rod to a steering arm that moves the nearest front wheel. In recirculating-ball steering, the thread between the worm and nut is filled with balls.
Figure 10: The Steering System Link to the image: (https://repairpal.com/suspension-steering) 2.2.7 The Intake and Exhaust Systems
Combustion requires air, fuel, and heat; certain ratios of all three are necessary if an engine is to operate. The purpose of the exhaust and intake processes is to remove the burned gases at the end of the power stroke and admit a dmit fresh charge for the next cycle. c ycle. a
Intake System
The intake system’s job is to regulate the flow of clean, filtered air at the right temperature to the engine and to provide vacuum to operate other devices. Most factory intake systems are designed 15
to generate as little noise as possible. The intake system, shown in Figure 11 below, also pulls crankcase vapors into the intake stream so the engine can burn them. Older carbureted engines do not have much of intake system. Usually just an air filter mounted on top of the carburetor, which is mounted on the intake manifold, is enough for those engines. Modern day vehicles have much more intake plumbing to accommodate smaller engine bays which have much technology more packed into them.
Figure 11: The Intake System Link to the image: (https://www.coolcaraircon.co.uk/how-car-air-conditioning-works/) b
The Exhaust System
The exhaust system, shown in Figure 12 below, is an assembly in a vehicle's engine that takes care of the burnt gas that the engine produces. It consists of exhaust pipes, through which exhaust gas flow through from one chamber to another, a header, which collects the same gas from different cylinders and directs it to the pipes, a catalytic converter, which converts the pollutant gases produced during combustion into less harmful substances, a muffler, which reduces engine noise, and a turbocharger, which increases engine power. The exhaust system is vital to any vehicle because the life and performance of the vehicle's engine depends on it. An engine cannot function well if there is back pressure trapped in it. Trapped exhaust gas chokes an engine and stops it from doing productive work. As a result, the vehicle cannot run smoothly and silently, or in the worst cases, will not run at all. 16
Figure 12: The Exhaust System Link to the image: (https://mechanicalserviceswi.com/auto-repair/exhaust-system)
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CHAPTER THREE: HANDS-ON ACTIVITIES CARRIED OUT 3.1 Introduction
During my training at DCVI, I participated in different practical activities where I applied the theoretical knowledge and skills acquired in class into real world problem solving situations. The activities included among others; Clutch adjustment, diagnosis and correction of battery failure, tire replacement, diagnosis and correction of power steering faults of a car and replacement of hydraulic oil of a truck. They are detailed below.
3.2 Diagnosis and correction of failure of a car battery
Battery failure is often reported and is one of the major causes of vehicle breakdowns. With modern vehicles full of complex and sensitive electrical equipment that constantly draw current from the battery, an ever-increasing number of mechanical faults from new and older vehicles alike are battery related. However, the expense and inconvenience of battery failure could be heavily reduced by regular battery maintenance. Figure 13 below shows the operation. 3.2.1 Common faults of the car battery, their causes and remedies
The following are the common faults associated with the car battery; their causes and corrections. a
Low charge
This is caused by leaving the battery in uncharged condition for a long time and also when battery usage exceeds battery capacity. Solution: The best solution for this problem is to recharge the battery. A jump start as well as a trickle charger can be used for this operation. A trickle charger is most commonly used. It delivers electricity to the battery from a power outlet in a slow, steady stream. It has an electric cord with a plug and two jumper cables with alligator clips. b Sulphation If the battery is allowed to stand in a discharged state either on or off the vehicle for a long period of time, a chemical reaction takes place plac e which wh ich permanently permanentl y impairs the performance and life of the battery. It can be seen as a fine white/grey coating of the positive plate. This is called Sulphation. Solution: Clean the battery terminal. c
Wear and tear due to ageing
As the battery is charging and discharging, the active materials within the battery plates are in motion in order to release electricity stored by the battery. This leads to the wear and tear of the battery when used for a long period of time. 18
Remedy: Replace the battery. d
Incorrect application
This is when the battery is not correctly applied or installed. Therefore, it cannot function properly on the vehicle. Remedy: Ensure that the correct battery in the right condition has been used in the right application. e
Low acid stratification
This is when the electrolyte on the stratified battery concentrates on the bottom causing the upper half of the battery to be poor. Remedy: Replace the electrolyte. f
Low acid level
This is when the level of the acid in the battery is not enough as required. Remedy: Refill the battery to required level. g
Slipping
This occurs due to incorrectly adjusted alternator cha rging the belt. Remedy: Adjust the alternator to required recommendations. h
Overcharging
If the alternator regulator is not set properly, an alternator voltage control circuit fails. Then the battery can be subjected to an excessive charge. If left unche cked for a long time, the battery will overheat and will start to evaporate the ele ctrolyte. Remedy: Replace regulator with another. i Electrical faults These are caused by excessive ex cessive use of electric consumers for example air conditioning, long standing time without recharge, vehicle lightings and haz ard flashers left on. Remedy: Recharge the battery; lightings and flashers should not be left on. 3.2.2 Fault found with the battery
After the diagnosis, it was found that the battery h ad low charge. The problem probl em was corrected by recharging the battery.
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3.2.3 Tools and equipment used to recharge the battery
The following tools were used to recharge the battery; Trickle charger, Power stroke, Manual sand paper pad and a pair of pliers. 3.2.4 Technical procedures followed
The following procedures were followed to recharge the battery; a. The battery terminals were checked and cleaned using a manual sand paper. b. The cell caps were removed. c. The charger cables were attached with the car turned off. d. The charger was turned on for the battery to charge itself. e. The battery was checked to find out whether it worked after charging and it functioned properly.
Figure 13: Recharging the battery 3.3 Replacement of water pump of a Cesspool truck
The engine of a vehicle needs coolant just as much as it needs oil. Engine coolant helps protect against high heat. It is cycled from the radiator throughout the engine, absorbing heat from engine operation and then allowing that heat to wick away into the atmosphere at the Radiator. The water pump is the key to making the entire system work. It is an impeller pump, buried under the timing belt cover on the side of the engine. The pump is operated by the drive belt of 20
the engine – as the belt turns, the pump turns. Blades on the pump force the coolant to flow through the engine. Figures 14 and 15 below show the operation. When the water pump fails or is beginning to wear out, it can lead to complete engine failure. The water pump is the key to making the entire system work. Like any other mechanical device, they will produce a few warning signs that they are wearing out. 3.3.1 Common faults with water pumps, their causes and remedies Table 2 below shows the common faults with water pump, their causes and remedies. The water pump experiences many faults. Table 2: Water pump troubleshooting chart FAULT
Weep-hole leakage. Appearance: The internal mechanical seal of the pump seals the shaft towards the cooling circuit, protecting the bearings by preventing coolant from passing into the bearing assembly. When a water pump is new, some seepage from the weep hole is normal as it takes about ten minutes of operation for the mechanical seal to properly seat itself (break-in period). More pronounced seepage and drips from the weep hole after this break-in period or a large coolant bleed mark around the weep hole are abnormal and indicate impending water pump failure. Leakage from the mounting surface. Appearance: Seepage drips or large coolant bleeds marks on or around the mounting surface or on the housing.
POSSIBLE CAUSE
REMEDY
Contaminated coolant is the main cause of weep hole leakage
Thoroughly flush the cooling system before installing the new pump and refill the system with the recommended coolant of the manufacturer of the vehicle
Improper water pump installation or improper use of the seals/gaskets or sealant.
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In case of a recently installed new water pump, carefully remove, check and reinstall the water pump.
Rust and corrosion.
Contaminated coolant, noncompatible coolant or mixing coolants of different chemistries.
Appearance: Rust and corrosion on the surfaces of the water pump, for example corrosion of the impeller fins Another possible cause may makes the pump ineffective in be a defective pressure cap moving the coolant. causing air bubbles, accelerating the rust process.
Deposit build-up. Appearance: Deposits, sludge and scale build up on the inside, clogging the water pump and hampering proper functioning of its individual components. Cavitation. Appearance: Vapor cavities (bubbles) in the coolant collapse with explosive force, pock marking the individual components of the pump. The pockmarked areas then corrode away. Damaged bearing. Appearance: With the engine off, check the condition of the bearing by looking for any side-to-side play at the shaft. Apply hand pressure – pressure – there there should be no play at all. Also, rumbling or screeching noises coming from the water pump indicate a worn bearing. Damaged or broken shaft. Appearance: The shaft is bent or broken. A clean break indicates an instantaneous
Contaminated coolant, noncompatible coolant or mixing coolants of different chemistries.
The formation of bubbles at the coolant inlet of the pump. As the pressure increases increases in the system, system, the bubbles implode cause harm.
Replace the water pump. Thoroughly flush the cooling system before installing the new water pump and refill the system with the recommended coolant of the manufacturer of the vehicle. Inspect the pressure cap and replace if defective Replace the water pump. Thoroughly flush the cooling system before installing the new pump and refill the system with the correct vehicle manufacturer’s manufacturer’s recommended coolant Replace the water pump. Thoroughly flush the cooling system before installing the new pump and refill the system with the correct vehicle manufacturer’s recommended coolant
Misaligned belt causes Replace the water pump and excessive wear. An overmake sure to inspect the belt tensioned belt causes overload drive system: belt, tensioner, on the bearing, accelerating pulleys, belt tension and wear. A damaged mechanical alignment. seal allows coolant to leak through the bearings and wash away the lubricator.
A misaligned belt causes Replace the water pump and excessive wear. An overmake sure to inspect the belt tensioned belt imposes a drive system: belt, tensioner, powerful bending force on the pulleys, belt tension and 22
fracture caused by sudden overload or imbalance. If the broken shaft is discolored (usually blue), the damage was gradual, indicating excessive heat build-up before the shaft broke.
Seal leakage-dirty system
Casting breakage
shaft resulting in shaft bending alignment. or early shaft fracture. If equipped with a water pump Excessive vibrations due to mounted fan, inspect the fan lack of maintenance. or fan clutch assembly. The fan may not be squarely mounted on the shaft. A bent or damaged fan, a worn spacer, or a worn or damaged fan clutch could also be factors contributing to the break. Thoroughly flush a contaminated system before replacing the water pump. Cooling system contamination Check the system pressure. Use correct coolant mixture. Use distilled water where necessary. Carefully inspect pulley, belt alignment and fan/fan clutch Excessive vibration assembly, replacing any bent or worn components. Take proper precautions when filling your radiator, especially when the engine may be very hot.
Seal leakage-clean system.
Thermal shock
Allow an overhead engine to sit and cool before adding coolant. Then restart engine and allow it to run while slowly adding the remainder. Never start the engine without coolant.
3.3.2 Fault found with the water pump
The water pump was worn out which could lead to complete engine failure. This prompted its replacement. 23
3.3.3 Tools and equipment used to replace the pump
A new water pump, ring spanner, box spanner, combination spanner and an adjustable spanner. 3.3.4Technical procedures followed
a. The radiator was drained by opening the petcock valve at the bottom of the radiator. This was done when the engine was cold. b. The fan belt was removed, carefully noting how it was routed before removing it in order to reinstall it correctly afterwards. c. Any other accessories that were blocking access to the pump were removed. This included the fan, fan shroud, timing belt cover, or any brackets. d. The water pump was unbolted from the engine. e. The pump mounting surface was cleaned to remove all traces of old gaskets. The mounting surface must be clean and dry before installing the new pump. f. The gasket was positioned on the new pump using gasket sealer or adhesive as required, and then the new water pump was bolted to the engine. g. The cooling system was refilled.
Figure 14: The removed water pump
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Figure 15: The unit that houses the water pump 3.4 Replacement of hydraulic oil of a FAW truck
Hydraulic fluid is the medium by which power is transferred in hydraulic machinery. Common hydraulic fluids are based on mineral oil or water mineral oils, synthetic fluids and fire-resistant fluids. The primary function of a hydraulic fluid is to convey power from one point to another. There are other important functions of hydraulic fluid such as protection of the hydraulic machine components, lubrication of system components, transfer and dissipation of heat, and provision p rovision of a seal to maintain pressure. Examples of equipment that use hydraulic oil include; Excavators and backhoes, Hydraulic Hydraulic brakes, Power steering systems, Transmissions and Garbage trucks. trucks. The operation is shown in Figure 16 below. 3.4.1 Dangers involved in working with hydraulic fluids
There are several dangers involved while dealing with hydraulic fluids. These include the following; a. Health problems.
People can become exposed to the chemicals in hydraulic fluids. The exposure may be due to inhalation, ingestion, or touch. There are instances of people suffering from skin irritation or weakness in hands while handling hydraulic fluids. There are also cases of intestinal 25
bleeding, pneumonia, or death through hydraulic fluid ingestion though no serious hazards haz ards are reported with hydraulic fluid inhalation. Similar to ingestion, fluids can be accidentally injected into the skin as well. This takes place when the high-pressure hydraulic system hose is disconnected and toxic fluids are leaked and injected into the skin. If there is a small leak in the hydraulic pipe and someone runs there hand along it, at 2000 psi, they can easily incur an injection of hydraulic fluid and may not even be aware that it happened until gangrene begins to set in. b. Fire dangers.
When working with hydraulic fluid, there is every chance that the hydraulic fluid gets heated to high temperatures. And it is evident that most petroleum-based hydraulic fluids will burn and thereby create explosions and burns. c. Environmental problems. When the hydraulic hose or pipe leaks, the chemicals of the fluids can either stay on top of the soil or sink into the ground. If the chemicals get mixed in a water body, they will sink to the bottom. In fact in such cases the chemicals can stay there for more than a year. Aquatic life can absorb the toxic hydraulic fluid, leading to illness or death to the animal or anything higher on the food chain. For example, a hawk that eats a fish that has been contaminated by hydraulic fluid that was mixed in water could become ill as well. d. Fluid texture problems. Although the slimy texture of hydraulic fluids may not seem like a danger or a problem, a spill can cause a person to slip and fall. Also when there is fluid on the hands of a person, it can cause him to slip while climbing on a machine. It can also cause the operator op erator to lose steering control. 3.4.2 Safety precautions when dealing with hydraulic fluids
Certain safety precautions need to be followed when handling hydraulic fluids as discussed below; a. In order to avoid skin irritations, it is necessary to wash contaminated skin immediately. It is also necessary to keep your clothing clean. b. Always wear masks and gloves while using hydraulic fluids. c. To avoid environmental dangers, there is a biodegradable hydraulic fluid option, though it is more expensive. d. To avoid fires, materials and fluids soaked in hydraulic fluid should be stored in sealed metal containers and disposed of at proper places. e. To check for leaks, use cardboard.
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3.4.3 Common faults with the hydraulic system
Generally, improper hydraulic system operation can be traced to one of the following deficiencies: insufficient fluid level, the presence of air in the system, contamination by foreign material, incorrect adjustment of components, internal or external fluid leakage, mechanical damage to components, wrong fluid type t ype or viscosity and excessive temperatures. 3.4.4 Solutions to the common faults
The following tips, tools and techniques should be considered for appropriate use to curb the faults. a. The contaminant test. Obtain an oil sample in a clean, clear jar and let it sit overnight. Any contamination will settle to the bottom of the container and will remain attracted to the bottom surface for viewing even when the container is turned over. b. The crackle test . If water is suspected but not obvious, obtain an oil sample and place two or three drops of the oil on a hot plate. The drops will crackle, pop or sizzle if any water is present. Remember that any water may be harmful depending upon the equipment type or process. c. The “poor man’s” particle count. It is a simple inspection of the filter of the machine. Cut the filter open, spread the media out on a bench and view any contaminant with a magnifying glass or microscope. Run a magnet under the filter media. Any ferrous material will move with the magnet. This should immediately call for a ferrographic analysis of an oil sample. d. The color test. Any brownish or darkening discoloration of the oil which is an obvious change, suggests that oxidation has begun. Any discoloration should be immediately investigated by sending an oil sample for a minimum of viscosity and acid number analysis. If the viscosity has increased by 10% or more of new oil and the acid number has increased substantially, the fluid may have reached the end of its service life and thus replacement is required. e. The high temperature test. Dark discoloration of the hydraulic fluid suggests that oxidation is occurring. If high temperatures are suspected, they could be caused by external leaks which create hot spots at valves or cylinders, plugged coolers or kinked or damaged hoses, relief valve pressure settings too high, or o il of too high viscosity. In all cases, the use of predictive maintenance tools such as infrared thermograph or an infrared thermometer using laser beams to instantly locate hot spots will locate the h igh temperature areas. f. The internal leakage test. When a hot spot is located, such as at a cylinder barrel or servo valve, the use of a hand held ultrasonic tester will locate the leak. During a leak, a liquid moves away from high pressure. As it passes through the leak site, a turbulent flow is generated that has strong ultrasonic sound waves that can be monitored. The intensity of the ultrasound will be loudest at the actual leak site. These ultrasonic sounds cannot be heard by the human ear. Very often, external leaks will cause hot spots that will burn the hand of a 27
troubleshooter, so care must be taken when attempting to locate high temperature problems. g. The excessive noise test. An ultrasonic tester can also be used to monitor conditions such as cavitation or aeration at hydraulic pump inlets or other components, as well as locating electrostatic discharge noise at filters or reservoirs. Electrostatic charges may be generated in hydraulic fluids by turbulence, high fluid velocities, internal fluid friction, fluids flowing in ungrounded piping or when fluid discharges on to any free surface of the reservoir, particularly if there is free air present in the fluid. Electrostatic discharge most often manifests itself as a clicking sound as the charge repeatedly builds and then discharges to a surface of lower voltage through sparking. The increased use of synthetic fluids and mineral base oils with non-metallic anti-wear additives have resulted in fluids with low conductivity, increasing the potential for accumulated static charge levels. In severe cases, electrostatic discharge can result in etching, pitting or carbon deposits at the surfaces of the area where the discharge occurred and may leave burn marks or other damage on the filter element media. h. The foam and air entrainment inspection. As noted earlier, a darkening color of hydraulic of hydraulic fluid suggests that oxidation is occurring. Oxidation rates are related directly to high temperatures and excessive air entrainment combined with high pressure. At atmospheric pressure and corresponding temperature, oils contain about 10%by 10%b y volume of dissolved air. At 200 psi (1400 kPa), oils can absorb about 140% by volume. The dissolved air provides the oxygen that is necessary to promote oxidation and oxidation rates rapidly increase as temperatures rise above 140ºF (60ºC) and hydraulic pressures increase to their normal operating ranges. Dissolved air in oil under pressure will tend to produce foam as a s pressure is released and the air comes out of solution. This free air is now trapped inside operating cylinders and other components, which will cause erratic and spongy operation and increased temperatures. If hydraulic systems begin to display erratic, spongy operational behavior or cylinder extension and retraction speeds are slower than normal or erratic in nature, there is a good possibility that tha t there is excessive air entrainment in the hydraulic system. The presence of entrained air is readily apparent by the bubbly, opaque appearance of the fluid in the reservoir. When excessive levels of entrained air are suspected, inspect all system connections where air may be drawn into the system. Examples are; loose pump inlet connections, the fluid return line is broken or no longer below the oil level in the reservoir, the pump shaft seal has failed, inadequate or broken reservoir baffle plates, suction side of circuits are leaking or have loose connections. Suction leaks (where air is being drawn into a component or circuit) can easily be located by applying hydraulic oil to the connection. If the oil disappears, the troubleshooter has located the air leak! 28
3.4.5 Recommendations on hydraulic systems
As hydraulic systems improve and operating pressures increase, much more attention to predictive maintenance and reliability will be required. Two areas of concern will be a requirement for improved filter design, selection and installation and hydraulic system flushing techniques after a component failure has occurred. In the first instance, more consideration will be required for improved filter installation where increased vibration and/or higher pressure pulsation will require mitigation. In the second instance, mobile filtration systems and portable hydraulic fluid purifiers will become mandatory, if hydraulic system reliability is to be improved and maintained. 3.4.6 Faults found with the hydraulic oil
Diagnosis of the hydraulic oil of the truck, revealed the following faults that necessitated its replacement; a. Hydraulic oil had deteriorated. When the hydraulic oil is used for a long time, it deteriorates and thus has to be replaced. b. The base oil was degraded. c. The additive package was depleted. 3.4.7 Tools and equipment used to replace the hydraulic oil
The tools and equipment used to change the hydraulic oil were; a ring spanner, box spanner, Hammer, combination spanner, funnel, bucket, clean piece of cloth and new hydraulic oil. 3.4.8 Technical procedures followed
The following procedures were observed during the operation; a.
The system was drained while the fluid was ho t to keep contaminants in suspension.
b.
The fluid was emptied from cylinders, accumulators and lines that could not drain properly. The oil left in the reservoir was pumped out.
c. d. e. f.
The reservoir was wipe-cleaned with lint free rags and rust and free paint were removed. Filter elements, strainers, and housing were cleaned. The system was refilled with new hydraulic fluid making sure to vent high points.
g.
The system was restored and checked for proper operation after which it functioned.
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Figure 16: Draining the hydraulic oil 3.5 Replacement of leaf springs of a FAW truck
The rear suspension under some vehicles is supported by a pair of leaf springs made up of multiple leaves (strips) of spring steel. A leaf spring is a component of suspension systems of some vehicles. They are composed of several (or occasionally just one) thin strips of metal, called leaves, arranged on top of each other to form a single curved piece. Typically, they have three or four individual leaves that make a set of springs. Leaf springs have a specific curvature, and this curvature and the number of leaves in the spring pack; determine the load capacity and the ride height of the vehicle. The curvature also helps the spring absorb impact. The bending of the leaves and the friction between them as they slide slightly over each other while bending, absorb the weight of the vehicle as well as any bumps. Leaf springs should be replaced when they are worn out, flattened out, cracked or broken. Figures 17 and 18 below show the operation.
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3.5.1 Functions of the suspension of the vehicle
The suspension of the vehicle serves three major functions; they are to; Support the vehicle b. Absorb impacts from bumps, potholes, and other road irregularities a.
c.
Allow the vehicle to turn in response to the driver’s inputs. (The steering system can be considered part of the suspension, or its own system, but either way the suspension has to allow for movement of the wheels as the vehicle turns).
3.5.2 The purpose of leaf springs
Leaf springs are appropriate for spreading heavy loads over a large area (because they are attached to the vehicle at the ends, which may be several feet apart) and for suspension designs that incorporate a “solid” axle rather than independent suspension for each wheel especially of heavy vehicles such as trucks. These factors render leaf springs appropriate for trucks and other heavy vehicles but less so for cars, as such designs tend to have undesirable effects on the handling of the vehicle. As independent (as opposed to solid axle) rear suspensions have become increasingly common on cars, leaf springs are now found primarily on trucks, vans, SUVs and trailers. 3.5.3 Maintenance of leaf springs
Multi-leaf Multi-leaf springs occasionally get “sticky” as dirt works its way in between the leaves; the effect can be to make the ride slightly stiffer, but this is rarely a significant problem. The attachment points will need to be checked periodically and lubricated in some cases as specified by the manual of the manufacturer, and regular maintenance should be carried out. If the body of the car seems to sit too low over the wheels, this sagging is usually due to the leaf springs having bent slightly over time, and the solution is to have them replaced. 3.5.4 Fault found with the leaf springs
The leaf springs were broken as depicted by inspection. This necessitated their removal and replacement. 3.5.5 Safety precautions while replacing leaf springs The following precautions should be observed when replacing the leaf springs; a. Always wear safety glasses when working carrying out the operation. b. Wear other personal protective equipment (PPE) when necessary, for example latex gloves or closed toe shoes.
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3.5.6 Tools and equipment used to replace the leaf springs
The following tools and equipment were used to replace the leaf springs of the truck; A ratchet, hammer, Box spanner, combination spanner (24-24), floor jack, trolley jack, lubricant (oil); ring spanners (numbers16, 18, 19 and 30), wrenches and Jack stands. 3.5.7 Technical procedures followed to replace the leaf springs a.
The vehicle was parked on a solid, level surface to ensure that it did not roll or lean when raised.
b.
Using a floor jack, the rear of the vehicle was lifted up enough for the axle assembly to hang freely.
c. d. e. f. g. h.
The vehicle was secured with jack stands on both sides for safety before starting any work. The rear axle assembly was supported with a floor jack close to the spring. The lower bolt was removed from the shock absorber. The axle was lowered to relieve tension on the spring. The U-bolts and spring retainer bracket were removed. The parking brake cable was removed from the retainer bracket.
i. j.
The rear axle was carefully lowered since leaf springs were moun ted on top of the axle. The rear shackle bolts were loosened.
k.
The leaf springs were supported with a jack stand and the leaf spring front and rear eye bolts were removed. The leaf springs were removed from the vehicle.
l. m.
The front bushings of the new springs were placed into the front mounting brackets, the front eye bolts and nuts were installed with the bolt heads towards the center of the vehicle.
n.
The rear bushings of the new springs were placed into the rear shackles and the rear eye bolts and nuts were loosely installed.
o.
The axles were adjusted to place the leaf springs center bolts into the holes on the axle pads.
p.
The U-bolts and retainer brackets were installed; the U-bolt nuts were snagged down but not tightened.
q.
The parking brake cable was reattached and the lower shock mount was attached to the axle bracket. Steps (d) through (q) were repeated for the other side of the truck.
r. s. t. u.
The truck was lowered to the ground and all bolts torqued to the recommended specifications. The leaf springs repair was verified and the vehicle was aligned. The vehicle was road-tested and found to operate well.
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Figure 17: Removing the broken leaf springs
Figure 18: The broken leaf springs that were removed 33
3.6 Replacement of a tire of a garbage truck
Tires are often the most neglected components on vehicles, but better care should be taken of them, our lives on the ride depend on them. They support the overall weight of the vehicle and thus must be in good conditions to function properly. They are one of the most important components of the vehicle. The tire tread area making contact with the road is relatively small – – only about the size of the palm of the hand - so if tires are worn or damaged it can seriously affect the safety and handling of the vehicle. Figure 19 below shows the operation. 3.6.1 Common tire problems and their solutions
Tires wear abnormally as the result of excessive sharp braking or rapid acceleration. The guide below for what to look out for will help when inspecting tires: a. Illegal wear. When a tire is worn, it needs replacing immediately. Any tire in this condition has been used far beyond the legal tread depth limit. b. Misalignment . A misaligned tire will be worn noticeably more on one side than the other. For example, a tire aligned inwards will wear more on the outside than the inside. If the tire is aligned outwards the inner shoulders of the tire wear more than the outer shoulders. Any tire in this state should be replaced immediately. c. Camber wear . Cambered wheels result in increased wear on the outer edge of a tire. Cambering occurs due to poor fitting and this significantly reduces the lifespan of a tire. Wheels should be repaired. d. Emergency braking . If an emergency stop is performed, the tire wears enormously in an isolated area and can lead to deflation. If an emergency stop maneuver has recently been executed, check the tires for isolated damage. e. Cuts and tears . Observe the sidewalls of the tires. Sharp objects such as nails, glass or metal can cause a cut or tear in the tire. If a cut or tear is spotted it can render your tire unserviceable. Tires in this state should be replaced immediately. f. Impact damage . If a vehicle hits an object at high speed such as a kerb, a bulge may be may be visible in the side wall of the tires. The area of the bulge or egg highlights the location of casing damage. The damage should be diagnosed and fixed immediately. 3.6.2 Minimizing tire problems
Tires are the only point of contact that the vehicle has with the road and as such, they need to be in good working condition at all times to ensure the safety of the users. To minimize tire problems and thus maximize the life of tires and achieve optimal performance from the vehicle, observe the following: a. Ensure that tires are correctly inflated . Driving with incorrect tire pressures can affect handling and braking of a vehicle, particularly in wet conditions, and can seriously compromise safety of users. In some cases, tires are over-inflated which inhibits vehicle handling and causes excessive wear on the centre strip of a tire. Driving on severely under-inflated tires can cause heat build-up and eventually a premature failure. Check tire 34
b.
c.
d. e.
pressure regularly and before every long trip. Observe the load capacity. Do not exceed the load capacity relative to the load index of the tires. Overloading a vehicle increases strain upon the tires which raises temperatures, causes rapid wear and significantly heightens the risk of receiving impact damage that leads to premature failure. Consult the vehicle handbook to find pressures should there be need to fully load the vehicle. Manage the speed of the car . Driving at very high speeds over long and short distances causes tire temperatures to increase, which in some cases can lead to tire damage. If tires are not correctly inflated, driving at high speeds also increases the likelihood of sudden tire failure and rapid loss of air. To maximize the life of tires, observe speed limits and avoid aggressive acceleration/deceleration. Make use of spare tires . If any damage to a tire or wheel is seen, replace tire with spare tire and have tires checked by a professional. Inspect the tires. It may not always be noticed if one of the tires has been damaged. Inspect tires regularly for wear and any damage to avoid any sudden problems. Also, have a professional inspect the tires every year. Note: Unfortunately many tire problems are unavoidable. Tires can be checked regularly but still fall foul of an errant nail, piece of metal or a pesky pothole. However, if the guidelines are followed and tell-tale signs of potential problems are looked out for; longest life possible out of tires can be got.
3.6.3 Fault found with the tire
Inspection of the tire indicated that it was worn out; this prompted its removal and replacement. 3.6.4 Safety procedures while replacing tires
While changing tires, the following safety measures should be observed. a. The tire levers should not be sharp. This is because the tube might get cut during the process. b. While changing tires, put little French chalk inside the t ire. It works as a lubricant. c. Sometimes, tire bead may get stuck on rim due to rusty rim. Do not apply extra force. In this case, put little water on tire bead and leave it for 20 minutes and then try again. d. Always put few amounts of air inside the tube before fixing bead of tire. This air prevents p revents the cutting of tube and keeps it away from lever and rim. e. While inflating tires, ensure that the tire is resting nicely on the rim flange. This setting is very important for heavy duty vehicles especially espe cially Tractor tires. f. After the steps to change tires have been completed, tighten the nuts and only then, remove the jack. g. After removing the Jack, the nuts should be tightened again for safety.
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h. The wheel nuts should be checked more often in new vehicles-after every few hundred kilometers. The reason for regular checking in case of new vehicles is that wheel nuts might become loose due to the paint. 3.6.5 Tools and equipment used to replace the tire
A hammer, ring spanner, wrench, floor jack, trolley jack, combination spanner, box spanner and an open spanner. 3.6.6 Technical procedures followed
a. b. c. d. e. f. g. h. i. j. k. l. m. n. o. p.
The truck was parked on a flat surface. The parking brake was applied and the truck put in to park position. Rocks were placed in front of the front and back tires. The jacks were placed under the frame near the tire that was to be replaced. The jacks were raised until they were supporting but not lifting the car. The hubcap was removed and the nuts loosened by turning them counterclockwise. The jacks were pumped to lift the tire off the ground. The nuts were removed by turning them counterclockwise until they loosed. The tire was then removed. The spare tire was placed on the hub, its rim aligned with wheel bolts and lug nuts put in positions. The nuts were tightened using the wrench in a star pattern. The truck was lowered without applying full weight on the tire, and the nuts were tightened further. The truck was fully lowered to the ground. The jacks were removed. The nuts were tightened finally and the hubcap replaced. The truck was road-tested and the new tire was found to be functioning well.
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Figure 19: Removing the tire 3.7 Troubleshooting starter motor of a Toyota Pick-up
Before an engine starts, it must first be cranked. Turning the engine over draws air and fuel into the cylinders and compresses the mixture so it can be ignited to provide power. Cranking the engine also generates the ignition and crankshaft position sensor signals that are needed to fire the spark plugs and operate the fuel injectors. Cranking the engine is achieved with the help of the starter. So if a starter fails to crank the engine or turns too slowly, the engine will not start. Unfortunately, starting problems are not always simple to diagnose. Sometimes the starter motor is blamed for a hard starting or no-start condition that is not the fault of the starter. As a result, some starters are replaced unnecessarily. One way to avoid such predicaments is to bench-test old starters to make sure they are defective before they are replaced by new n ew ones. After removing your old o ld starter, you can test the current draw and cranking speed of the starter. Figure 20 below shows the operation. 3.7.1 Common symptoms of a failing or bad Starter, their causes and remedies
They include the following: a. Grinding noise. When the starter drive gear is worn out or not engaging properly, they will often produce a grinding noise that is similar to the one that is heard if engine is started and then accidentally the starter is hit again. If the grinding symptom is ignored, it 37
b.
c.
d.
e.
f. g.
h.
may also result in damage to the engine flywheel. It should be diagnosed immediately upon detection. Freewheeling . Freewheeling occurs when the engine is cranked and simply a whining noise is heard from the starter without the engine cranking. When this occurs, it means the starter gear is not engaging with the flywheel. This is a bad situation that could result in the need for a starter replacement. If this is occurring, the vehicle should be be serviced as soon as possible. Smoke. Seeing smoke is cause for immediate concern, and can indicate a few different problems with the starter or starting circuit. Smoke usually indicates that too much power is being drawn through the electrical supply to a starter, either because the starter is shorted, has been operated too long without a rest or there is a connection problem. Smoke might also be accompanied by a burning smell. If smoke is seen, the vehicle should be serviced by a professional as soon as possible. Oil soak. The starter is often located around the bottom of the engine and is vulnerable to soaking from leaks from the engine oil or other drive train fluids. An oil-soaked starter likely has a short life remaining. Consider correcting the leak and replacing the starter before a malfunction occurs. Malfunctioning solenoid. The solenoid transmits electrical current from the battery to the starter motor when the key is turned in the ignition of the vehicle and also pushes the starter drive into the flywheel to allow cranking. Without the solenoid, the starter does not work. If the key is turned to the crank position and nothing happens, try jiggling the transmission gear shift lever first. If the engine still will not crank, there might be something wrong with the solenoid. When the key is turned to crank the engine, nothing happens . The engine does not turn over. When the key is turned to crank the engine and all that is heard is one loud click . The engine does not turn over; or when the key is turned to crank the engine and the engine turns over very but very slowly and an d then stops. When the battery is good but the car fails to start.
3.7.2 Safety procedures while troubleshooting a starter motor
While troubleshooting a starter motor, certain safety measures need to b e observed. They include the following: a. If you have to lift up the car or truck to access the starter motor: Use jack-stands to support the car or truck off the ground, and use safety glasses while working underneath the vehicle. b. You will need a helper to crank the engine as you perform some of the tests, and to help you perform the very important Voltage Drop Test. c. When jumpering 12 Volts to the S-terminal wire (circuit) make sure you do not short-toground your jumper wire. 38
3.7.3 Tools and equipment used
Spanners (Open, fixed, adjustable, combination and box), safety glasses, jack stands, a voltmeter, pair of pliers, screwdriver, jack, and multi-meter. 3.7.4 Technical procedures followed
a. The state of charge of the battery was determined. b. The ignition switch was checked if it was sending power to the solenoid. c. The starter motor was checked if the problem lied in itself d. The solenoid was tested to see if it was working. 3.7.5 Testing the starter
a. The battery was tested first, using a multi-meter. b. The starter motor was tested if it was receiving 12 Volts on its battery circuit. c. The starter motor was tested if it was receiving the start signal from the ignition switch. d. The starter battery and ground circuits were voltag e-drop-tested. e. Using a jumper-wire, 12 volts was applied to the Start signal wire. f. The engine was turned by hand to eliminate a locked-up engine or a locked-up AC compressor.
Figure 20: Testing the voltage being received by the starter
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3.8 Adjusting the clutch of a garbage truck
If the clutch is maintained properly, it can be good for the life of the vehicle. Most modern vehicles with manual transmissions have self-adjusting clutches that require no adjustment, but models without self-adjustment should be properly adjusted. Figures 21 and 22 below show the operation. 3.8.1 Common faults with the clutch system, their causes and remedies They are summarized in Table 3 below.
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Table 3: Clutch diagnosis/troubleshooting chart FAULT POSSIBLE CAUSES 1. Improper linkage adjustment. 2. Improper pedal travel. 3. Loose linkage. 4. Faulty pilot bearing. 5. Faulty driven disc. 6. Fork off ball stud. 7. Clutch disc hub binding on clutch gear spline. 8. Clutch disc warped or bent. 9. Loose pivot rings in Fails to Release (Pedal pressed cover assembly. to floor). Shift lever does not move freely in and out of reverse gear. 1. Improve adjustment (no lash). 2. Oil soaked driven Slipping. disc. 3. Worn facing or facing torn from disc. 4. Warped pressure plate or flywheel. 5. Weak diaphragm spring. 6. Driven plate not seated in. 7. Driven plate overheated.
Grabbing or Chattering.
1. Oil on facing. Burned or glazed facings. 2. Worn splines on clutch gear. 3. Loose engine mountings. 4. Warped pressure plate or flywheel. 5. Burned or smeared resin on fly wheel or pressure plate. 41
1. 2. 3. 4. 5. 6.
7. 8. 9. 1. 2.
3. 4. 5.
6. 7. 1. 2. 3. 4. 5.
REMEDY Adjust linkage. Trim bumper stop and adjust linkage. Replace as necessary. Replace bearing. Replace disc. Install fork onto stud. Lightly lubricate fingers at release bearing. Repair or replace clutch gear and/or disc. Replace disc (run out should not exceed 0.020″). Replace plate and cove coverr asse assemb mbll . Adjust linkage to specifications. Install new disc and correct leak at its source. Replace disc. Replace pressure plate or flywheel. Replace pressure plate. (Be sure lash is checked before replacing plate.) Make 30 to 40 normal starts. Caution: Do not overheat. Allow to cool – – check check lash. Install new disc and correct leak. Replace transmission clutch gear. Tighten or replace mountings. Replace pressure plate or flywheel. Sand off if superficial, replace burned or heat checked parts.
Rattling-Transmission Click
Throw-out bearing noise with clutch fully engaged Noisy
Pedal stays on floor when released Hard pedal effort
1. Weak retracting springs. 2. Release fork loose on ball stud or in bearing groove. 3. Oil in driven plate damper. 4. Driven plate damper spring failure. 1. Improper adjustment. No lash. 2. Release bearing binding on transmission bearing retainer. 3. Insufficient tension between clutch fork spring and ball stud. 4. Fork improperly installed. 5. Weak linkage return spring. 1. Worn release bearing. 2. Fork off ball stud (heavy clicking). 3. Pilot bearing loose in crankshaft.
1. Bind in linkage or release bearing. 2. Springs weak in pressure plate. 3. Springs being over traveled. 1. Bind in linkage. 2. Driven plate worn.
1. Replace pressure plate. 2. Check ball stud and retainer. 3. Replace driven disc. 4. Replace driven disc.
1. Adjust linkage. 2. Clean, re-lubricate, check for burrs, and nicks among others. 3. Replace fork. 4. Install properly. 5. Replace spring. 1. Replace bearing. 2. Install properly and lubricate fork fingers at bearing. 1. Lubricate and free up linkage and release bearing. 2. Replace pressure plate. 3. Adjust linkage to get proper lash, make sure proper pedal stop (bumper) is installed. 1. Lubricate and free linkage. 2. Replace driven plate.
3.8.2 Faults found with the clutch system
Inspection of the clutch system revealed the following faults that prompted the operation. a. The clutch was getting worn out. b. There was difficulty shifting-the shifter was not moving freely.
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3.8.3Tools and equipment used to adjust the clutch
The following tools and equipment were used to carry out the operation A drive ratchet, socket, large screwdriver , drop Light, piece of wood, floor pads, f an an and an extension cord 3.8.4 Technical procedures followed a. The parking brake was engaged, the gear shifter put in neutral, and the clutch pedal pressed to the floor. b. The access opening for the clutch assembly was located under the truck just behind the oil pan. A torch light was used to see where the adjustment plate was. c. With the clutch pedal depressed, a large flathead screwdriver was used as a lever to rotate the flywheel assembly till the adjustment plate was at the bottom a nd fully accessible. d. Using a socket, only the left-hand l eft-hand bolt which secures the retaining strap was removed. e. The retaining strap was removed and set aside. f. Using a wrench, the adjusting bolt on o n the splined shaft was rotated clockwise (handle towards the side of the driver) until the proper p roper amount of clutch adjustment was achieved. g. Reassembling was done and the car was road-tested and found to be functioning properly.
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Figure 21: The opened clutch system
Figure 22: The removed pressure and clutch plates
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3.9 Panel beating a Pajero Shogun
Panel beating refers to repairing vehicle bodies back to their factory state after having been damaged. This work is done by an auto-body mechanic called the panel beater. The process is a highly labor intensive, involving various techniques to remove dents, shape panels to match the original contours then smooth, resurface and spray paint the damaged areas. Spraying a car involves applying to the body of the car, a jet of vapor or tiny drops of coating or paint to make the car look good. The operation is shown in Figures 23 and 24 below. 3.9.1Reasons for the operation
The operation was carried out in order to: 1. Remove the dents developed during the damage. 2. Prepare the body of the car for spray painting. 3. Bring back the body of the vehicle to the factory state. 3.9.2 Tools and equipment used
Hand hammer, body file, rough sand paper, wooden piece, filler paste, pad, hardener, spot putty, spraying gun, primer, wooden holder, smooth sand paper, water, undercoat duke metallic paint, undercoat duke silver, thinner, clear coating, Hacksaw blade, Detergents, ring spanners 14 combined, papers and cellotape. 3.9.3 Safety precautions for the operation
The following are the safety measures that should be observed during the operation: a. Always use correct spanners when removing the body parts of the vehicle that is to be panel-beaten and/or sprayed. b. Great care should be taken when using the hammer to bring back the shape of the body of the vehicle in such a way that the body is not further damaged. c. Carefully use the body file as it may hurt the user and also cause further damages to the part being filed. d. Always wear protective gears during the operation. e. Ensure that the vehicle is properly parked. 3.9.4 Technical procedures followed
The following procedures were observed during the operation. a. The vehicle was parked on a clean, dry, solid surface, the parking brake was applied. b. The dents on the body parts of the vehicle were identified by visual inspection, where the damaged parts are surveyed using the eyes, and feeling inspection where the hands are gently moved on the surface to feel the dented parts. c. The vehicle was properly cleaned with water and dried with a piece of cloth. 45
d. The hand hammer and piece of cloth were used to bring back the shape of the body of the vehicle that was damaged, taking care not to disorganize the permanently designed marks on the body surface of the vehicle. e. The damaged parts were filed off; properly making sure that the outer coating is also filed. This was done using the body bod y file. f.
The filler paste was mixed with the hardener in appropriate proportion with the hardener and then the mixture was applied on the body parts that had been filed. The filler paste was applied using pads.
g. The parts were left to dry and then were again slightly filed with the body file and then sanded properly using rough sand paper to smoothen the body surfaces. h. Spot putty was then applied using a pad so as to fill in the scratches developed during filing and sanding processes. i.
The parts were left to dry and then were sanded properly with smooth sand paper 500. While doing so, water was applied frequently. The parts were then again left to dry.
j.
The parts that were not supposed to be sprayed were covered using pieces of papers and mended with masking tape.
k. Using spraying gun, the primer was then applied to the body surfaces, to prevent rusting from occurring. It was then left to dry. l.
The body was then sprayed with undercoat duke silver using a spraying gun. It was then left to dry after which it was sprayed with undercoat metallic.
m. Clear coating was then sprayed to the body surface. The clear coating was mixed with hardener and thinner to make the body surface to shine brightly and look newer.
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Figure 23: Sanding using smooth sand paper 500
Figure 24: Covering the parts that were not supposed to be sprayed
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CHAPTER FOUR: SKILLS ACQUIRED, CHALLENGES FACED RECOMMENDATIONS AND CONCLUSION 4.1 Introduction
This chapter covers the skills acquired from the field attachment training, challenges faced at work, recommendations and conclusion. 4.2 Experience gained/achievements from the training
From the industrial training, I acquired a number of skills and knowledge through the application of the theoretical knowledge learnt in class into the practical operations which led to an improvement and widening of my engineering knowledge. All activities were carried out while taking note of all the safety precautions necessary to prevent accidents and produce the desired results accurately and in time while using the right tools and following the correct procedures. The following were the achievements from the training. a. b. c. d. e. f. g. h. i.
Maintenance of vehicles and equipment. Exposure to the demands and challenges of the workplace. Appreciation of the professional and therefore better work ethics. Improved confidence in problem-solving. How to relate to different categories of people likely to be met in real-life situation. Opportunity to meet and work with potential employers. Gained first-hand experience working as an engineering professional. I learnt how to work with other engineering professionals and the value of teamwork in engineering. I was able to increase my technical, interpersonal and communication skills, both oral and written.
4.3 Challenges faced during the training
During the training, a number of challenges challen ges were faced as given below. a. Most technical words used in motor vehicle work were not familiar to me but more research and inquiries were made from the senior mechanics and through reading of vehicle manuals to get acquainted with them. b. In the earlier days of the training, several accidents and injuries were sustained for example cuts on fingers and legs; however with time, vigilance on work was increased which reduced on injuries. c. Language barrier. The language used at the work place was not familiar to me but usually requested them to kindly translate for me and also efforts were made to learn the key words normally used while carrying out operations. 48
d. While making inquiries from the senior mechanics on the operations being carried out, different reactions would be received from different people; some were welcoming while others were tough. So most of the research and inquiries were made with the friendly mechanics and serious efforts were made to befriend ever yone at the workshop. e. Delay of some spare parts of the vehicles which made some work not to be completed in time. f.
Most of the work needed use of heavy tools and machine components which made the work difficult, tiresome and time consuming. In such cases, help was sought from other people in the workshop to help especially in lifting the heavy machine components and tools.
g. Inadequate tools and equipment like spanners, cylinder head resurfacing machine, crankshaft regrinding machine, and water jet cleaner which is used to clean the radiator; caused delay of the work hence creating work backlogs. h. Unfavorable weather conditions like heavy rainfall often disrupted activities at the workshop. In such cases, operations were carried out under an erected structure, which however could only accommodate small vehicles. i.
Relating theoretical knowledge to practical situations was a great setback. However, through continuous research and persistent inquiries from the workshop technicians, it became easy.
j.
Limited time to share knowledge with all engineers and technicians due to tight schedules at the workshop.
k. Inadequate financial support to cater for my daily expenses like transport, meals and others. l.
Limited working space due to congestion in the workshop.
m. Inadequate safety guards during operation of some machines like air compressor which blows dust from air cleaners. n. Lack of well-designed training program and an immediate person who is responsible for the affairs of the trainees. This made trainees not to fully exploit some of the most important engineering aspects of the institution as there was no serious monitoring and also access to some of the sections was either not easy or prohibited without the permission of a supervisor. o. There was poor sanitation at the workshop. For example, toilets were shared equally by both male and female workers. This is risky to the health of workers. p. Too much bureaucracy which led to delay of work in the workshop as sometimes spare parts and other materials could not be accessed in time.
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4.4 Recommendations
Following what transpired during the industrial training especially the challenges I en countered, I recommend the following to the management mana gement of DCVI. a.
Proper waste management should be frequently carried out at the workshop. Rubbish should be collected together and either burnt or disposed off to keep the workshop clean every time. b. There should be a well-designed training program for trainees and an immediate person responsible for their affairs. c. All the necessary tools should be availed and close supervision carried out by registering all the tools and the corresponding workers using them so that in case of any tool loss, the particular worker is responsible and replaces them. d. More safety gadgets should be acquired especially for air compressing and panel beating e. More air compressors should be acquired so that more air filters can be cleaned within a short time. f. Cleaning air filters should be carried out from an open space where there is free circulation of air to protect the person carrying out the operation from dust and other harmful fumes. g. Scraps should be removed from working areas to give more working space as well as for safety purposes. h. There should be a scrap yard where scraps are collected and stored. i. Management should consider expanding the workshop so as to accommodate the ever-increasing volume of work at the workshop. j. Training duration should be extended since the mechanical engineering field is a very wide one and therefore cannot be fully exhausted within the allocated weeks of training. k. Materials should be acquired timely and availed immediately upon requisition, to avoid delay in carrying out work in the workshop. l. In a bid to improve sanitation of workers at the workshop, I recommend that male and female workers should use separate toilets. 4.5 Conclusion The internship was a fruitful experience. Through the application of the theoretical knowledge into real-life problem-solving situations, I gained a lot of experience especially in the automotive field. I also got insight into professional practice, learnt how life can be fruitful as well as challenging under employment; and how to face and deal with these challenges. It was also a great opportunity for developing personal networking activities and making contacts with influential people; which is of great value to me as far as my career is concerned. The training also enabled me to discover my strengths and weaknesses. This further helped me to identify areas to improve on. In a nutshell, I achieved most of my learning objectives from the training. 50
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