AUT 140 - Automotive Brakes Diagnosis and Repair

1. Demonstrate knowledge of hydraulic theory and general braking system operation  
2. Demonstrate knowledge of disk brake systems and perform a disk brake service
3. Demonstrate knowledge of drum brake systems and perform a drum brake service
4. Perform a master cylinder R&R, bleed master cylinder, and perform a complete hydraulic system bleed procedure
5. Perform a complete brake system inspection
6. Demonstrate knowledge of anti-lock braking systems and diagnose ABS concerns
7. Measure, mount, and cut drums/rotors on a bench-mounted brake lathe
8. Perform an on-car brake lathe machining procedure

1. General Brake Systems Diagnosis
   1. Complete work order to include customer information, vehicle identifying information, customer concern, related service history, cause, and correction.
   2. Identify and interpret brake system concern; determine necessary action.
   3. Research applicable vehicle and service information; such as brake system operation, vehicle service history, service precautions, and technical service bulletins.
   4. Locate and interpret vehicle and major component identification numbers
2. Hydraulic System Diagnosis and Repair
   1. Diagnose pressure concerns in the brake system using hydraulic principles (Pascal’s Law).
   2. Measure brake pedal height, travel, and free play (as applicable); determine necessary action.
   3. Check master cylinder for internal/external leaks and proper operation; determine necessary action.
   4. Remove, bench bleed, and reinstall master cylinder.
   5. Diagnose poor stopping, pulling or dragging concerns caused by malfunctions in the hydraulic system; determine necessary action.
   6. Inspect brake lines, flexible hoses, and fittings for leaks, dents, kinks, rust, cracks, bulging or wear; tighten loose fittings and supports; determine necessary action.
   7. Replace brake lines, hoses, fittings, and supports.
   8. Fabricate brake lines using proper material and flaring procedures (double flare and ISO types).
   9. Select, handle, store, and fill brake fluids to proper level.
   10. Inspect, test, and/or replace metering (hold-off), proportioning (balance), pressure differential, and combination valves.
   11. Inspect, test, and/or replace components of brake warning light system.
   12. Bleed and/or flush brake system.
   13. Test brake fluid for contamination.
3. Drum Brake Diagnosis and Repair
   1. Diagnose poor stopping, noise, vibration, pulling, grabbing, dragging, or pedal pulsation concerns; determine necessary action.
   2. Remove, clean, inspect, and measure brake drums; determine necessary action.
   3. Refinish brake drum; measure final drum diameter.
   4. Remove, clean, and inspect brake shoes, springs, pins, clips, levers, adjustors/self-adjustors, other related brake hardware, and backing support plates; lubricate and reassemble.
   5. Inspect and install wheel cylinders.
   6. Pre-adjust brake shoes and parking brake; install brake drums or drum/hub assemblies and wheel bearings.
   7. Install wheel, torque lug nuts, and make final checks and adjustments.
4. Disc Brake Diagnosis and Repair
   1. Diagnose poor stopping, noise, vibration, pulling, grabbing, dragging, or pulsation concerns; determine necessary action.
   2. Remove caliper assembly; inspect for leaks and damage to caliper housing; determine necessary action.
   3. Clean and inspect caliper mounting and slides/pins for operation; wear, and damage; determine necessary action.
   4. Remove, inspect and replace pads and retaining hardware; determine necessary action.
   5. Disassemble and clean caliper assembly; inspect parts for wear, rust, scoring, and damage; replace seal, boot, and damaged or worn parts.
   6. Reassemble, lubricate, and install caliper, pads, and related hardware; seat pads, and inspect for leaks.
   7. Clean, inspect, and measure rotor thickness, lateral runout, and thickness variation; determine necessary action.
   8. Remove and reinstall rotor. 
   9. Refinish rotor on vehicle; measure final rotor thickness.
   10. Refinish rotor off vehicle; measure final rotor thickness.
   11. Retract caliper piston on an integrated parking brake system.
   12. Install wheel, torque lug nuts, and make final checks and adjustments.
   13. Check brake pad wear indicator system operation; determine necessary action.
5. Power Assist Units Diagnosis and Repair
   1. Test pedal free travel; check power assist operation.
   2. Check vacuum supply to vacuum-type power booster.
   3. Inspect the vacuum-type power booster unit for leaks; inspect the check valve for proper operation; determine necessary action.
   4. Inspect and test hydraulically assisted power brake system for leaks and proper operation; determine necessary action.
   5. Measure and adjust master cylinder pushrod length.
6. Miscellaneous (Wheel Bearings, Parking Brakes, Electrical, Etc.) Diagnosis and Repair
   1. Diagnose wheel bearing noises, wheel shimmy, and vibration concerns; determine necessary action.
   2. Remove, clean, inspect, repack, and install wheel bearings and replace seals; install hub and adjust bearings.
   3. Check parking cables and components for wear, binding, and corrosion; clean, lubricate, adjust or replace as needed.
   4. Check parking brake and indicator system operation; determine necessary action.
   5. Check operation of brake stop light system; determine necessary action.
   6. Replace wheel bearing and race.
   7. Inspect and replace wheel studs.
   8. Remove and reinstall sealed wheel bearing assembly.
7. Electronic Brake, Traction and Stability Control Systems Diagnosis and Repair.
   1. Identify and inspect electronic brake control system components; determine necessary action.
   2. Diagnose poor stopping, wheel lock-up, abnormal pedal feel, unwanted application, and noise concerns associated with the electronic brake control system; determine necessary action.
   3. Diagnose electronic brake control system electronic control(s) and components by retrieving diagnostic trouble codes, and/or using recommended test equipment; determine necessary action.
   4. Depressurize high-pressure components of the electronic brake control system.
   5. Bleed the electronic control system hydraulic circuits.
   6. Remove and install electronic brake control system electrical/electronic and hydraulic components.
   7. Test, diagnose, and service electronic brake control system sped sensors (digital and analog), toothed ring (tone wheel), and circuits using a graphing multimeter (GMM)/digital storage oscilloscope (DSO)(includes output signal, resistance, shorts to voltage/ground, and frequency data).
   8. Diagnose electronic brake control system braking concerns cause by vehicle modifications (tire size, curb height, final drive ratio, etc.).
   9. Identify traction control/vehicle stability control system components.
   10. Describe the operation of a regenerative braking system.