| A. General |
| MHT3A001 |
Research vehicle service information, including fluid type, vehicle service history, service precautions, and technical service bulletins. |
| MHT3A002 |
Identify brake system components and configurations (including air and hydraulic systems, parking brake, power assist, and vehicle dynamic brake systems). |
| MHT3A003 |
Identify brake performance problems caused by the mechanical/foundation brake system (air and hydraulic). |
| MHT3A004 |
Use appropriate electronic service tool(s) and procedures to diagnose problems; check, record, and clear diagnostic codes; interpret digital multimeter (DMM) readings. |
| B. Air Brakes: Air Supply and Service Systems |
| MHT3B001a |
Inspect, test, repair, and/or replace air supply system components such as compressor, governor, air drier, tanks, and lines; inspect service system components such as lines, fittings, mountings, and valves (hand brake/trailer control, brake relay, quick release, tractor protection, emergency/spring brake control/modulator, pressure relief/safety); determine needed action. |
| MHT3B001a |
Inspect, test, repair, and/or replace air supply system components such as compressor, governor, air drier, tanks, and lines; inspect service system components such as lines, fittings, mountings, and valves (hand brake/trailer control, brake relay, quick release, tractor protection, emergency/spring brake control/modulator, pressure relief/safety); determine needed action. |
| MHT3B001b |
Inspect, test, repair, and/or replace air supply system components such as compressor, governor, air drier, tanks, and lines; inspect service system components such as lines, fittings, mountings, and valves (hand brake/trailer control, brake relay, quick release, tractor protection, emergency/spring brake control/modulator, pressure relief/safety); determine needed action. |
| MHT3B001c |
Inspect, test, repair, and/or replace air supply system components such as compressor, governor, air drier, tanks, and lines; inspect service system components such as lines, fittings, mountings, and valves (hand brake/trailer control, brake relay, quick release, tractor protection, emergency/spring brake control/modulator, pressure relief/safety); determine needed action. |
| MHT3B001d |
Inspect, test, repair, and/or replace air supply system components such as compressor, governor, air drier, tanks, and lines; inspect service system components such as lines, fittings, mountings, and valves (hand brake/trailer control, brake relay, quick release, tractor protection, emergency/spring brake control/modulator, pressure relief/safety); determine needed action. |
| MHT3B001e |
Inspect, test, repair, and/or replace air supply system components such as compressor, governor, air drier, tanks, and lines; inspect service system components such as lines, fittings, mountings, and valves (hand brake/trailer control, brake relay, quick release, tractor protection, emergency/spring brake control/modulator, pressure relief/safety); determine needed action. |
| MHT3B001f |
Inspect, test, repair, and/or replace air supply system components such as compressor, governor, air drier, tanks, and lines; inspect service system components such as lines, fittings, mountings, and valves (hand brake/trailer control, brake relay, quick release, tractor protection, emergency/spring brake control/modulator, pressure relief/safety); determine needed action. |
| MHT3B001g |
Inspect, test, repair, and/or replace air supply system components such as compressor, governor, air drier, tanks, and lines; inspect service system components such as lines, fittings, mountings, and valves (hand brake/trailer control, brake relay, quick release, tractor protection, emergency/spring brake control/modulator, pressure relief/safety); determine needed action. |
| MHT3B002a |
Test gauge operation and readings; test low pressure warning alarm operation; perform air supply system tests such as pressure build-up, governor settings, and leakage; drain air tanks and check for contamination; determine needed action. |
| MHT3B002b |
Test gauge operation and readings; test low pressure warning alarm operation; perform air supply system tests such as pressure build-up, governor settings, and leakage; drain air tanks and check for contamination; determine needed action. |
| MHT3B002c |
Test gauge operation and readings; test low pressure warning alarm operation; perform air supply system tests such as pressure build-up, governor settings, and leakage; drain air tanks and check for contamination; determine needed action. |
| MHT3B002d |
Test gauge operation and readings; test low pressure warning alarm operation; perform air supply system tests such as pressure build-up, governor settings, and leakage; drain air tanks and check for contamination; determine needed action. |
| MHT3B003 |
Demonstrate knowledge and understanding of air supply and service system components and operations. |
| MHT3B004 |
Inspect air compressor drive gear components (gears, belts, tensioners, and/or couplings); determine needed action. |
| MHT3B005 |
Inspect air compressor inlet; inspect oil supply and coolant lines, fittings, and mounting brackets; repair or replace as needed. |
| MHT3B006 |
Inspect and test air tank relief (safety) valves, one-way (single) check valves, two-way (double) check valves, manual and automatic drain valves; determine needed action. |
| MHT3B007 |
Inspect and clean air drier systems, filters, valves, heaters, wiring, and connectors; determine needed action. |
| MHT3B008 |
Inspect and test brake application (foot/treadle) valve, fittings, and mounts; check pedal operation; determine needed action. |
| C. Air Brakes: Mechanical/Foundation Brake System |
| MHT3C001 |
Inspect, test, repair, and/or replace service brake chambers, diaphragms, clamps, springs, pushrods, clevises, and mounting brackets; determine needed action. |
| MHT3C002 |
Identify slack adjuster type; inspect slack adjusters; perform needed action. |
| MHT3C003 |
Check camshafts (S-cam), tubes, rollers, bushings, seals, spacers, retainers, brake spiders, shields, anchor pins, and springs; perform needed action. |
| MHT3C004 |
Inspect rotor and mounting surface; measure rotor thickness, thickness variation, and lateral runout; determine needed action. |
| MHT3C005 |
Inspect, clean, and adjust air disc brake caliper assemblies; inspect and measure disc brake pads; inspect mounting hardware; perform needed action. |
| MHT3C006a |
Remove brake drum; clean and inspect brake drum and mounting surface; measure brake drum diameter; measure brake lining thickness; inspect brake lining condition; determine needed action. |
| MHT3C006b |
Remove brake drum; clean and inspect brake drum and mounting surface; measure brake drum diameter; measure brake lining thickness; inspect brake lining condition; determine needed action. |
| MHT3C007 |
Diagnose concerns related to the mechanical/foundation brake system including poor stopping, brake noise, premature wear, pulling, grabbing, or dragging; determine needed action. |
| D. Air Brakes: Parking Brake System |
| MHT3D001 |
Inspect, test, and/or replace parking (spring) brake chamber. |
| MHT3D002 |
Inspect, test, and/or replace parking (spring) brake check valves, lines, hoses, and fittings. |
| MHT3D003 |
Inspect, test, and/or replace parking (spring) brake application and release valve. |
| MHT3D004 |
Manually release (cage) and reset (uncage) parking (spring) brakes. |
| MHT3D005 |
Identify and test anti-compounding brake function; determine needed action. |
| E. Hydraulic Brakes: Hydraulic System |
| MHT3E001 |
Check master cylinder fluid level and condition; determine proper fluid type for application. |
| MHT3E002 |
Inspect hydraulic brake system for leaks and damage; test, repair, and/or replace hydraulic brake system components. |
| MHT3E003 |
Check hydraulic brake system operation including pedal travel, pedal effort, and pedal feel; determine needed action. |
| MHT3E004 |
Diagnose poor stopping, premature wear, pulling, dragging, imbalance, or poor pedal feel caused by problems in the hydraulic system; determine needed action. |
| MHT3E005 |
Test master cylinder for internal/external leaks and damage; replace as needed. |
| MHT3E006 |
Test metering (hold-off), load sensing/proportioning, proportioning, and combination valves; determine needed action. |
| MHT3E007 |
Test brake pressure differential valve; test warning light circuit switch, bulbs/LEDs, wiring, and connectors; determine needed action. |
| MHT3E008 |
Bleed and/or flush hydraulic brake system. |
| F. Hydraulic Brakes: Mechanical/Foundation Brake System |
| MHT3F001 |
Clean and inspect rotor and mounting surface; measure rotor thickness, thickness variation, and lateral runout; determine necessary action. |
| MHT3F002a |
Inspect and clean disc brake caliper assemblies; inspect and measure disc brake pads; inspect mounting hardware; perform needed action. |
| MHT3F002b |
Inspect and clean disc brake caliper assemblies; inspect and measure disc brake pads; inspect mounting hardware; perform needed action. |
| MHT3F003 |
Remove, clean and inspect brake drums; measure brake drum diameter; measure brake lining thickness; inspect brake lining condition; inspect wheel cylinders; determine serviceability. |
| MHT3F004 |
Check disc brake caliper assembly mountings and slides; replace as needed. |
| G. Hydraulic Brakes: Parking Brake System |
| MHT3G001 |
Check parking brake operation; inspect parking brake application and holding devices; adjust, repair, and/or replace as needed. |
| H. Power Assist Systems |
| MHT3H001 |
Check brake assist/booster system (vacuum or hydraulic) hoses and control valves; check fluid level and condition (if applicable). |
| MHT3H002 |
Check operation of emergency (back-up/reserve) brake assist system. |
| MHT3H003 |
Identify concerns related to the power assist system (vacuum or hydraulic), including stopping problems caused by the brake assist (booster) system; determine needed action. |
| MHT3H004 |
Inspect, test, repair, and/or replace hydraulic brake assist/booster systems, hoses, and control valves. |
| I. Vehicle Dynamic Brake Systems (Air and Hydraulic): Antilock Brake System (ABS), Automatic Traction Control (ATC) System, and Electronic Stability Control (ESC) System |
| MHT3I001 |
Observe antilock brake system (ABS) warning light operation including trailer and dash mounted trailer ABS warning light; determine needed action. |
| MHT3I002 |
Observe automatic traction control (ATC) and electronic stability control (ETC) warning light operation; determine needed action. |
| MHT3I003 |
Identify stopping concerns related to the vehicle dynamic brake systems: ABS, ATC, and ESC; determine needed action. |
| MHT3I004 |
Diagnose problems in the vehicle dynamic brake control systems; determine needed action. |
| MHT3I005 |
Check and test operation of vehicle dynamic brake system (air and hydraulic) mechanical and electrical components; determine needed action. |
| MHT3I006 |
Test vehicle/wheel speed sensors and circuits; adjust, repair, and/or replace as needed. |
| MHT3I007 |
Bleed ABS hydraulic circuits. |
| MHT3I008 |
Verify power line carrier (PLC) operation. |
| J. Wheel Bearings |
| MHT3J001 |
Clean, inspect, lubricate, and/or replace wheel bearings and races/cups; replace seals and wear rings; inspect spindle/tube; inspect and replace retaining hardware; adjust wheel bearings; check hub assembly fluid level and condition; verify end play with dial indicator method. |
| MHT3J002 |
Identify, inspect, and/or replace unitized/preset hub bearing assemblies. |