A5 Brakes
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TABLE OF CONTENTS Chapter 1: An Introduction to the Automotive Service Excellence Certification Program .......................................................................... 12 An Overview of chapter One ........................................................................................ 12 The Objectives .............................................................................................................. 12 Who is Eligible to Participate in the Automotive Service Excellence Certification Tests .................................................................................................. 13 The Benefits of Acquiring an Automotive Service Excellence Certificate .................. 14 Summary ...................................................................................................................... 16 Sample Questions to Chapter One of the AudioLearn Study Guide ............................17 Chapter 2 – Brakes Test A5 Overview ........................................................ 20 Overview of Chapter 1 .................................................................................................. 20 Learning Objectives ..................................................................................................... 20 Introducing the AudioLearn Brakes Study Guide ....................................................... 21 Brakes Test A5 ............................................................................................................. 22 Brakes Test A5 Test Specifications and Task Lists ..................................................... 26 The Test Specification and Task Lists Table ............................................................... 30 Summary ...................................................................................................................... 31 Key Takeaway .............................................................................................................. 32 Sample Questions for Chapter 1 .................................................................................. 33
Chapter 4 – Hydraulic, Power Assist and Parking, Brake Systems Diagnosis and Repair – Lines and Hoses .............................................. 77 An Overview of Chapter 3 ............................................................................................ 77 The Learning Objectives .............................................................................................. 77 Task A.2.1 – Diagnose Poor Stopping, Pulling, or Dragging Caused by Problems in the Lines and Hoses; Determine the Needed Repairs. ..................... 78 Task A.2.2 – Inspect Brake Lines and Fittings for Leaks, Dents, Kinks, Rust, Cracks, or Wear; Tighten Loose Fittings and Support. ......................................... 79 Task A.2.3 – Inspect Flexible Brake Hoses for Leaks, Kinks, Cracks, Bulging, Wear or Corrosion; Inspect for Loose Fittings and Support; Determine the needed Repairs .......................................................................................................80 Task A.2.4 – Replace Brake Lines, Hoses, Fittings, and Supports; Fabricate Brake Lines Using Proper Material and Flaring Procedures (Double Flare and ISO Types) ....................................................................................................... 81 Bending Brake Lines .................................................................................................... 83 Task A.2.5 – Inspect Brake Lines and Hoses for Proper Routing and Support ......... 85 Summary ...................................................................................................................... 86 Key Takeaways ............................................................................................................. 87 Sample Questions for Chapter 3 .................................................................................. 89 Chapter 5– Hydraulic, Power Assist and Parking, Brake Systems Diagnosis and Repair – Valves and Switches ........................................ 93 An Overview of Chapter 4. ........................................................................................... 93 The Learning Objectives .............................................................................................. 93 Task A.3.1 – Diagnose Poor Stopping, Pulling or Dragging Caused by Problems in the Hydraulic System Valves; Determine the Needed Repairs ........ 95 Task A.3.2 – Inspect, Test, Replace, and Adjust Load or Height Sensing-type Proportioning Valves.............................................................................................. 96
Task A.3.3 – Inspect, Test, and Replace Brake System Warning Lights, Indicators, Switches, Sensors and Circuits; Test, Adjust, and Repair or Replace Brake Stop Light and Brake Pedal Position Switch Sensor, Lamps, and Related Circuits ............................................................................................... 98 Summary .....................................................................................................................101 Key Takeaways ........................................................................................................... 102 Sample Questions for Chapter 4 ................................................................................ 103 Chapter 6 – Hydraulic, Power Assist and Parking, Brake Systems Diagnosis and Repair – Bleeding, Flushing, and Leak Testing ............ 107 An Overview of Chapter 5 .......................................................................................... 107 Task A.4.1 – Diagnose Poor Stopping, Pulling, Dragging or Incorrect Pedal Travel Caused by Problems in the Braking Fluid; Determine the Needed Repairs.................................................................................................................. 108 Task A.4.2 – Bleed and Flush Hydraulic System Using Manual, Pressure, Vacuum or Gravity Methods .................................................................................110 Brake Bleeding ............................................................................................................ 112 Task A.4.3 – Pressure Test the Brake Hydraulic System ........................................... 117 Task A.4.4 – Select, Handle, Store, and Install Proper Brake Fluids (including silicone fluids). Fill Master Cylinder to Proper Level ........................................... 118 Inspecting Brake Fluids ............................................................................................. 120 Summary ..................................................................................................................... 121 Key Takeaways ........................................................................................................... 122 Sample Questions for Chapter 5 ................................................................................ 124
Chapter 7 – Hydraulic, Power Assist and Parking, Brake Systems Diagnosis and Repair – Power Assist Units......................................... 128 An Overview of Chapter 6 .......................................................................................... 128 The Learning Objectives ............................................................................................ 128 Task A.5.1 – Inspect and Test Brake Pedal Linkage for Binding. Looseness, and Adjustment; Determine the Needed Repairs ............................................... 130 Task A.5.2 – Test Pedal Free Travel with and Without Engine Running to Check Power Booster Operation ........................................................................... 131 Task A.5.3 – Check Vacuum Supply (Manifold or Auxiliary Pump) to Vacuumtype Power Booster .............................................................................................. 132 Task A. 5.4 – Diagnose Vacuum-type Power Booster Unit for Vacuum Leaks and Proper Operation; Inspect the Check Valve for Proper Operation; Repair, Adjust or Replace Parts as Necessary ..................................................... 133 Checking the Valve for Proper Operation ................................................................. 135 Task A.5.5 – Diagnose Hydro-boost System for Leaks and Proper Operation; Repair or Replace Parts as necessary; Refill and Bleed System following Manufacturer’s Specifications.............................................................................. 136 Summary .................................................................................................................... 139 Key Takeaways ........................................................................................................... 140 Sample Questions for Chapter 6 ................................................................................ 142 Chapter 8 – Hydraulic, Power Assist and Parking, Brake Systems Diagnosis and Repair – Parking Brake ............................................... 146 An Overview of Chapter 7 .......................................................................................... 146 Learning Objectives ................................................................................................... 146 Task A. 6.1 – Diagnose Parking Brake System Operation Including Electronic Parking Brakes; Inspect Cables and parts for Wear, Rust, and Corrosion; Clean or Replace Parts as Necessary; Lubricate Assembly ................................. 148
Task A. 6.2 – Adjust Parking Brake Assembly; Check Operation ............................ 150 Task A. 6.3 – Test the Parking Brake Indicator Light, Switch, and Wiring .............. 151 Task A.6.4 – Retract Integral and Electronic Brake Caliper Pistons According to the Manufacturers’’ Specifications .................................................................. 153 Task A.6.5 – Adjust Calipers with Integrated Parking Brakes according to the Manufacturers’ Recommendations...................................................................... 156 Summary .....................................................................................................................157 Key Takeaways ........................................................................................................... 158 Sample Questions for Chapter 7 ................................................................................ 159 Chapter 9 – Drum Brake Diagnosis and Repair ....................................... 163 Types of Brake Drums and Their Components ......................................................... 164 Task B.1 – Diagnose Poor stopping, Pulling, Dragging, or Incorrect Pedal Travel caused by Drum Brake Hydraulic Problems; Determine the Needed Repairs.................................................................................................................. 168 Task B.2 – Diagnose Poor Stopping, Noise, Pulling, Grabbing, Dragging, Pedal Pulsation or Incorrect Pedal Travel caused by Drum Brake Mechanical Problems; Determine the Needed Repairs ...................................... 169 Task B.3 – Remove, Clean, Inspect, and Measure Brake Drums; Follow Manufacturers’ Recommendations in Determining need to Machine or Replace .................................................................................................................. 171 Task B.4 – Machine Drums According to Manufacturers’ Procedures and Specification ......................................................................................................... 174 Task B.5 – Using Proper Safety Procedures, Remove, Clean, and Inspect Mechanical Brake Components such as Shoes and Lining, Springs, Pins, Self-adjuster, Levers, Clips, Brake Backing Plates and other related Brake Hardware; Determine the Needed Repairs ..........................................................175
Task B.6 – Lubricate Brake Shoe, Support Pads on Backing Plate, Selfadjuster Mechanism and other Brake Hardware ................................................. 177 Task B.7 – Inspect Wheel Cylinder for Leakage, Operation, and Mounting; Remove and Replace Wheel Cylinders; Bleed System ........................................ 178 Task B.8 – Install Brake Shoes and Related Hardware ............................................ 179 Task B.9 – Pre-adjust Brake Shoes and Parking Brake Before Installing Brake Drums or the Drum and Hub Assembly .............................................................. 180 Task B.10 – Reinstall Wheel, Torque Lug Nuts, and Make Final Checks and Adjustments .......................................................................................................... 181 Task B.11 – Diagnose Wheel Bearing Noises and Vibration Problems; Determine the Needed Repairs ............................................................................ 182 Task B.12 – Remove, Clean, Inspect, Repack, Wheel Bearings, or Replace Wheel Bearings and Races; Replace Seals, Replace Hub, and Bearing Assemblies; Adjust Wheel and Hub Bearings According to Manufacturer’s Specifications ....................................................................................................... 183 Summary .................................................................................................................... 185 Key Takeaways ........................................................................................................... 186 Sample Questions for Chapter 8................................................................................ 188 Chapter 10 – Disc Brake Diagnosis and Repair ........................................ 192 Task C.1 – Diagnose Poor Stopping, Pulling, Dragging or Incorrect Pedal Travel Caused by Disc Brake Hydraulic Problems; Determine the Needed Repairs.................................................................................................................. 193 Task C.2 – Diagnose Poor Stopping, Noise, Pulling, Grabbing, Dragging, Pedal Pulsation or Incorrect Pedal Travel caused by Disc Brake Mechanical Problems; Determine the Needed Repairs .......................................................... 194 Task C.3 – Retract Brake Caliper Pistons According to Manufacturers Recommendations ............................................................................................... 195
Task C.16 – Distinguish Between Brake Component Vibration and Tire or Wheel Vibration; Determine the Needed Repairs ................................................ 211 Summary .................................................................................................................... 212 Key Takeaways ........................................................................................................... 213 Sample Questions for Chapter 9 ................................................................................ 215 Chapter 11 – Electronic Brake Control Systems: Antilock Brake System (ABS), Traction Control System (TCS), and Electronic Stability Control System (ESC) Diagnosis and Repair ......................... 219 An Overview of Chapter 10 ........................................................................................ 219 The Learning Objectives ............................................................................................220 Task D.1 – Follow Manufacturers’ Service and Safety Precautions when Inspecting, Testing, and Servicing Electronic Brake Control System Hydraulic, Electrical, and Mechanical Components ........................................... 221 Task D.2 – Diagnose Increased Stopping Distance, Wheel Lock-up, False Activation, Pedal Feel, Pedal Travel, Pedal Pulsation, and Noise Concerns Associated with the Electronic Brake Control System; Determine The Needed Repairs .................................................................................................... 224 Task D.3 – Observe Electronic Brake Control System Indicator lights at Startup and During Road Test; Determine the Needed Repairs................................. 225 Task D.4 – Diagnose Electronic Brake Control system, Electronic Control Components, and Circuits Using On-board Diagnosis or the Recommended Test Equipment such as; Scan Tools, Digital Multi-meter, Digital Storage Oscilloscope; Determine the Needed Repairs ............................ 226 Task D.5 – Bleed and Flush the Electronic Brake Control Hydraulic System Following Manufacturers’ Procedures ................................................................. 228 Task D.6 – Remove and Install Electronic Brake Control System Components Following Manufacturers’ Procedures and Specifications; Perform Module Set-up and Initialization ...................................................................................... 229
Task D.7 – Test Diagnose and Service Electronic Brake Control System Sensors (speed, Yaw, Steering Angle, and Brake Pedal Position) and Circuits Following Manufacturers’ Recommended Procedures Including Output Signal, Resistance, Amperage, Shorts to Voltage and Frequency Data ...................................................................................................................... 231 Task D.8 – Diagnose Electronic Brake Control System Braking Concerns Caused by Vehicle Modifications (wheel and tire size, Curb Height, and Final Drive Ratio) and other Vehicle Mechanical and Electrical Modifications (Communication, security, and Radio) ........................................ 233 Task D.9 – Repair Wiring Harness and Connectors Following Manufacturers’ Procedures ............................................................................................................ 235 Task D.10 – Diagnose Brake Problems Resulting from Failures of Interrelated Systems for example; Electronic Stability Control, Antilock Brake, Traction Control .................................................................................................................. 237 Task D.11 – Clear Diagnostic Trouble Codes and Verify the Repair ......................... 238 Summary .................................................................................................................... 239 Key Takeaways ...........................................................................................................240 Sample Questions for Chapter Ten ........................................................................... 242 Practice Questions .................................................................................. 246 Answers to Sample Questions ................................................................. 280 Chapter 1 ................................................................................................................... 280 Chapter 2 .................................................................................................................... 281 Chapter 3 .................................................................................................................... 282 Chapter 4 .................................................................................................................... 283 Chapter 5 .................................................................................................................... 284 Chapter 6 .................................................................................................................... 285 Chapter 7 .................................................................................................................... 286
Chapter 8.................................................................................................................... 287 Chapter 9 ....................................................................................................................288 Chapter 10 .................................................................................................................. 289 Chapter 11...................................................................................................................290 Practice Questions ..................................................................................................... 291
CHAPTER 1: AN INTRODUCTION TO THE AUTOMOTIVE SERVICE EXCELLENCE CERTIFICATION PROGRAM AN OVERVIEW OF CHAPTER ONE The first chapter of the AudioLearn study guide covering the third test in the Automobile and Light Truck certification series provides a peek into the Automotive Service Excellence Certification program. The aim of this chapter is to help you better understand what you stand to gain by acquiring an Automotive Service Excellence certificate. Welcome to the first chapter of the Manual Drive Train and Axles study guide. The Manual Drive Train and Axle certification test is the third test in the series of tests provided by the Automotive Service Excellence organization. And the objectives of this introductory chapter include the following:
THE OBJECTIVES This chapter introduces the background behind the Automotive Service Excellence test, its history and its benefits to auto-repair technicians. Through the course of this chapter you will learn about the following: •
Why the Automotive Service Excellence program was formed and why it is important to every auto-repair technician.
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The importance of getting an Automotive Service Excellence certification for auto-repair technicians and,
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The benefits of having certified auto-repair technicians for light truck and automobile repair business or shops.
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The development of more vehicles in the nineteen-sixties and the increased purchasing power of Americans after the great depression led to an increase in the number of vehicle owners across the country. And with this increase in automobile ownership came a problem and the problem was how to efficiently diagnose, service and repair faulty automobiles. As a solution to this problem, hundreds of auto-repair technicians popped up in every nook and cranny of the United States offering repair services. But in three out of five cases, the auto-repair technician was out of his depth, the word ‘his’ is used here because auto-repair technicians of that time were mostly men. The unprofessionalism in the auto-repair field led to thousands of complaints and a need to bring sanity to the auto-repair industry and this was when the idea behind the Automotive Service Excellence organization was formed. In nineteen seventy – two, a couple of experienced auto-repair technicians came together to form the National Institute of Automotive Service Excellence organization. The National Institute of Automotive Service Excellence body was created as a non-profit organization with the aim of providing certification tests to auto-repair technicians. And with the passage of time, the organization’s name was shortened to Automotive Service Excellence and this name has stuck till date. Since then, the certification tests offered by the Automotive Certification excellence organization have become the standard for auto-repair technicians looking to legitimize their abilities. Today, you can now sit for the Automotive Service Excellence certification tests in more than seven hundred locations across the country.
WHO IS ELIGIBLE TO PARTICIPATE IN THE AUTOMOTIVE SERVICE EXCELLENCE CERTIFICATION TESTS It is important to note that the Automotive Service Excellence certification program is open to anyone interested in pursuing a career as an auto-repair technician. The certification program was also created as a means for experienced auto-repair technicians and even mechanical engineers to learn more about their respective fields. Therefore, whether you are a beginner or an experienced auto-repair technician, you have a lot to gain from participating in the certification program.
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The ASE certification test is open to everyone; you do not need to have passed any of the tests in the Automobile and Light Truck series in order to sit for the third test. The certification program does not require you to have a (GED) in order to be a participant. All that is required is for you to pay the fees and prepare to take the test.
THE BENEFITS OF ACQUIRING AN AUTOMOTIVE SERVICE EXCELLENCE CERTIFICATE Successfully sitting for an ASE test prepares you for a great career as an auto-repair technician in different ways. These different benefits can be reaped by individuals or businesses that understand the importance of getting their auto-repair technicians certified. Therefore, starting with the benefits individual auto-repair technicians stand to gain by acquiring an ASE certificate, we have: 1. ASE certified technicians earn the trust of automobile owners looking for professional auto-repair technicians to handle their vehicles. 2. Every reputable automobile workshop or business respects the effort a technician who puts into acquiring the ASE certificate. Therefore, a certified auto-repair technician has a great edge over other competing candidates when searching for a job. 3. The blue tag that comes with successfully acquiring an Automotive Service Excellence certificate bestows instant respect on the bearer or owner. This is because it showcases your beliefs on pursuing professional development in your profession. 4. Lastly, it is a great way to test your hands-on knowledge and abilities against thousands of professional auto-repair technicians across the United States. Now, taking a look at auto-repair businesses and the benefits they stand to gain by employing certified technicians, we have the following: 1. Auto-repair shops or businesses with ASE certified technicians already earn the trust of prospective customers without much effort. This is because customers have been trained to check for the certification sticker and seeing it increases their trust in the business’s services. 14
2. Working with only certified auto-repair technicians also earns an auto-repair business some respect among its peers. This is due to the fact that other competing auto shops know what it takes to become certified. 3. Organizations looking to outsource or hire automotive repair service providers, on long-term contracts, give preferences to businesses with certified technicians. This is because certified technicians highlights how important a business views the need for constant professional development. 4. Having certified technicians also increase the earning potential of an auto-repair business as customers are willing to pay more for the professional services they expect to receive. So, here we have covered the many advantages getting an Automotive Service Excellence certification can bring to your business. Therefore, if you are considering getting certified, we are happy to let you know that you are on the right track to earning your blue ticket or badge. Finally, it is important to know that candidates who have successfully passed an Automotive Service Excellence certification test will only receive the certificate after proving that they have acquired a 2 – year work experience in the related field.
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SUMMARY The first chapter of this AudioLearn study guide paints a clear picture of the Automotive Service Excellence certification program in order for you to know what exactly you are getting into. Therefore, the AudioLearn study guide covers what you stand to gain as a certified auto-repair technician and why you should consider getting certified.
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THE FUNDAMENTALS OF BRAKING To understand braking systems, it is important to know the different types of braking systems, how many braking options are in a vehicle, and what affects the function of a vehicle’s brakes. In every automobile and light truck vehicle, there are two types of braking system. These systems are the service brake and the parking brake system. You can view these systems in figure 2 of the AudioLearn Study Guide PDF.
Figure 2
The service brake is generally used in slowing down or completely stopping a vehicle and it is operated by stepping on a foot pedal generally located at the left side of the accelerating or gas pedal. The modern service brake consists of components such as the drum or disc brakes, brake pads, push rods, master cylinders, and valves. In some vehicles, disc brakes are used on all four wheels while for others disc brakes are used on the front wheel and drum brakes on the rear wheel. The parking brake is generally used for holding and keeping a vehicle in place when it is stationary or parked. This is why it is called the parking brake and it is generally located between the driver and passenger seats or on the steering wheel. The parking brake is
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Figure 3
EXHAUST BRAKES An exhaust braking system functions by restricting the flow of exhaust gases passing through the engine. Exhaust brakes achieve this by closing the valve located in the exhaust manifold which results in high pressure building up in the exhaust manifold and the engine’s cylinder. The restriction of the exhaust flow causes the engine speed to slow down thereby decelerating the vehicle. The exhaust braking system is used in heavy-duty vehicles such as tractors and trailers. 47
Figure 4.
PARKING BRAKES In earlier sections, it has been stated that vehicles are generally equipped with both a service brake and a parking brake. To accurately diagnose the parking brake system, an understanding of how it functions is needed. Parking brakes are mechanically operated systems which are used when parking an automobile or light truck. When applied, the parking brake generally applies the braking units or assembly to two wheels of the vehicle. There are different types of parking brake systems and they include transmission mounted parking brakes and drum-style parking brakes. Drum-style parking brakes are used on vehicles with disc brakes and mechanical linkages are used to operate this type of parking brakes. On the other hand, transmission mounted parking brakes use a small drum brake to prevent the vehicle’s drive shaft from turning. The parking brake system also consists of components such as parking brake cables, and the mechanisms designed for its application. 49
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