BRAKES

For every task in Brakes, the following safety task must be strictly enforced:

Comply with personal and environmental safety practices associated with clothing; eye protection; hand tools; power equipment; proper ventilation; and the handling, storage, and disposal of chemicals/materials in accordance with federal, state, and local regulations.

The first task in Brakes is to listen to and verify the operator's concern, review past maintenance and repair documents, and determine necessary action.

IV. BRAKES

A. Air Brakes Diagnosis and Repair

1. Air Supply and Service Systems

1. Diagnose poor stopping, air leaks, premature wear, pulling, grabbing, or dragging problems caused by supply and service system malfunctions; determine needed action. P-1

2. Check air system build-up time; determine needed action. P-1

3. Drain air reservoir tanks; check for oil, water, and foreign material; determine needed action. P-1

4. Inspect, adjust, and align compressor drive belts, pulleys, and tensioners; replace as needed. P-1

5. Inspect compressor drive gear and coupling; replace as needed. P-3

6. Inspect air compressor, air cleaner/supply; inspect oil supply and coolant lines, fittings, and mounting brackets; repair or replace as needed. P-2

7. Inspect and test system pressure controls: governor, unloader assembly valves, intake screens, filters, lines, hoses, and fittings; replace as needed. P-2

8. Inspect air system lines, hoses, fittings, and couplings; repair or replace as needed. P-1

9. Inspect and test air tank relief (safety) valves, one-way (single) check valves, two-way (double) check-valves, manual and automatic drain valves; replace as needed. P-1

10. Inspect and clean air drier systems, filters, valves, heaters, wiring, and connectors; repair or replace as needed. P-2

11. Inspect and test brake application (foot) valve, fittings, and mounts; adjust or replace as needed. P-2

12. Inspect and test stop light circuit switches, wiring, and connectors; repair or replace as needed. P-2

13. Inspect and test hand brake (trailer) control valve, lines, fittings, and mountings; repair or replace as needed. P-2

14. Inspect and test brake relay valve; replace as needed. P-2

15. Inspect and test quick release valves; replace as needed. P-2

16. Inspect and test front and rear axle limiting (proportioning) valves; replace as needed. P-2

17. Inspect and test tractor protection valve; replace as needed. P-1

18. Inspect and test emergency (spring) brake control valve(s); replace as needed. P-1

19. Inspect and test inversion valve; replace as needed. P-1

20. Inspect and test low pressure warning devices, wiring, and connectors; replace as needed. P-1

21. Inspect and test air pressure gauges, lines, and fittings; replace as needed. P-3

2. Mechanical/Foundation

1. Diagnose poor stopping, brake noise, premature wear, pulling, grabbing, or dragging problems caused by the foundation brake, slack adjuster, and brake chamber problems; determine needed action. P-1

2. Inspect and test service brake chambers, diaphragm, clamp, spring, pushrod, clevis, and mounting brackets; repair or replace as needed. P-2

3. Inspect and service manual and automatic slack adjusters; perform needed action. P-1

4. Inspect and replace camshafts, rollers, bushings, seals, spacers, retainers, brake spiders, shields, anchor spins, and springs. P-1

5. Inspect wedge brake spider, manual and automatic adjuster plungers, housing, and wedge assembly; repair or replace as needed. P-3

6. Inspect, clean, and adjust air disc brake caliper assemblies; determine needed repairs. P-3

7. Inspect and measure brake shoes, linings, or pads; perform needed action. P-1

8. Inspect and measure brake drums or rotors; perform needed action. P-1

3. Parking Brakes

1. Inspect and test parking (spring) brake chamber diaphragm and seals; replace parking (spring) brake chamber; dispose of removed chambers in accordance with local regulations. P-2

2. Inspect and test parking (spring) brake check valves, lines, hoses, and fittings; replace as needed. P-2

3. Inspect and test parking (spring) brake application and release valve; replace as needed. P-2

4. Manually release (cage) and reset (uncage) parking (spring) brakes in accordance with manufacturer's recommendations. P-1

IV. BRAKES

B. Hydraulic Brakes Diagnosis and Repair

1. Hydraulic System

1. Diagnose poor stopping, premature wear, pulling, dragging or pedal feel problems caused by the hydraulic system; determine needed action. P-1

2. Check and adjust brake pedal pushrod length. P-3

3. Inspect and test master cylinder for leaks and damage; replace as needed. P-1

4. Inspect for leaks and damage, brake lines, flexible hoses, and fittings; replace as needed. P-1

5. Inspect and test metering (hold-off), load sensing/proportioning, proportioning, and combination valves; replace as needed. P-2

6. Inspect and test brake pressure differential valve and warning light circuit switch, bulbs, wiring, and connectors; repair or replace as needed. P-2

7. Inspect wheel cylinders; replace as needed. P-1

8. Inspect disc brake caliper assemblies; replace as needed. P-1

9. Inspect/test brake fluid; bleed and/or flush system; determine proper fluid type. P-1

10. Test and adjust brake stop light switch, bulbs, wiring, and connectors; repair or replace as needed. P-1

2. Mechanical/Foundation

1. Diagnose poor stopping, brake noise, premature wear, pulling, grabbing, dragging, or pedal feel problems; determine needed action. P-2

2. Inspect and measure brake drums or rotors; perform needed action. P-2

3. Inspect and measure drum brake shoes and linings; inspect mounting hardware, adjuster mechanisms, and backing plates; perform needed action. P-1

4. Inspect and measure disc brake pads/linings; inspect mounting hardware; perform needed action. P-1

3. Power Assist Units

1. Diagnose poor stopping problems caused by the brake assist (booster) system; determine needed action. P-2

2. Inspect, test, repair, or replace power brake assist (booster), hoses, and control valves; determine proper fluid type. P-2

3. Check emergency (back-up, reserve) brake assist system. P-2

4. Air and Hydraulic Antilock Brake Systems (ABS) and Automatic Traction Control (ATC)

1. Observe antilock brake system (ABS) warning light operation; determine needed action. P-1

2. Diagnose antilock brake system (ABS) electronic control(s) and components using self-diagnosis and/or specified test equipment (scan tool, PC computer); determine needed action. P-1

3. Diagnose poor stopping and wheel lock-up caused by failure of the antilock brake system (ABS); determine needed action. P-1

4. Inspect, test, and replace antilock brake system (ABS) air, hydraulic, electrical, and mechanical components; perform needed action. P-1

5. Diagnose, service, and adjust antilock brake system (ABS) wheel speed sensors and circuits following manufacturer's recommended procedures (including voltage output, resistance, shorts to voltage/ground, and frequency data). P-1

6. Bleed the ABS hydraulic circuits following manufacturer's procedures. P-2

7. Observe automatic traction control (ATC) warning light operation; determine needed action. P-3

8. Diagnose automatic traction control (ATC) electronic control(s) and components using self-diagnosis and/or specified test equipment (scan tool, PC computer); determine needed action. P-3