Medium Heavy Vehicle Air Brakes 6 1

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1 Medium Heavy Vehicle Air Brakes 6 Student/intern information: Name Class Vehicle used for this activity: Year Make Model Odometer VIN Learning Objective / Task Parking Brake Inspect camshafts, rollers, bushings, seals, spacers, retainers, brake spiders, shields, anchor pins, and springs; replace as needed. Inspect, clean, and adjust air disc brake caliper assemblies; determine needed repairs. Inspect and measure brake shoes or pads; perform needed action. Inspect and measure brake drums or rotors; perform needed action NATEF Reference Number 2007 NATEF Priority Level 3A2-4 P-1 3A2-5 P-3 3A2-6 P-1 3A2-7 P-1 Recommended Resource Materials CDX Automotive program CDX etextbook Technical service bulletins, shop manuals, and any other information applicable to the specific vehicle or components you are working on Class notes Materials Required Vehicle with possible engine concern Vehicle manufacturer s workshop manual Manufacturer-specific tools depending on the concern Vehicle lifting equipment if applicable 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 protection; proper lifting practices; hand tools; power equipment; proper ventilation; and the handling, storage, and disposal of fuels/chemicals/materials in accordance with federal, state, and local regulations. Some Safety Issues to Consider Diagnosis of this fault may require test driving the vehicle on the school grounds or on a hoist, both of which carry severe risks. Attempt this task only with full permission from your supervisor/instructor and follow all the guidelines exactly. Caution: If you are working in an area where there could be brake dust present (may contain asbestos, which has been determined to cause cancer when inhaled or ingested), ensure you wear and use all OSHA-approved asbestos protective/removal equipment. Lifting equipment such as vehicle jacks and stands, vehicle hoists, and engine hoists are important tools that increase productivity and make the job easier. However, they can also cause severe injury or death if used improperly. Make sure you follow the manufacturer s operation procedures. Also make sure you have your supervisor/instructor s permission to use any particular type of lifting equipment. 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. Medium Heavy Vehicle Air Brakes 6 1

2 Always wear the correct protective eyewear and clothing and use the appropriate safety equipment, as well as fender covers, seat protectors, and floor mat protectors. Make sure you understand and observe all legislative and personal safety procedures when carrying out practical assignments. If you are unsure of what these are, ask your supervisor/instructor. Performance Standard 0 No exposure: No information or practice provided during the program; complete training required 1 Exposure only: General information provided with no practice time; close supervision needed; additional training required 2 Limited practice: Has practiced job during training program; additional training required to develop skill 3 Moderately skilled: Has performed job independently during training program; limited additional training may be required 4 Skilled: Can perform job independently with no additional training Task Inspect camshafts, rollers, bushings, seals, spacers, retainers, brake spiders, shields, anchor pins, and springs; replace as needed. 3A Inspect and test service brake chamber(s), including internal components. a. With reference to vehicle manufacturer s workshop manual, research the description and operation of the brake system for this vehicle including the researching of drum brake inspection and servicing procedures plus wheel assembly and brake drum(s) removal/installation procedures: i. List the procedure for servicing the service brake chamber, noting all safety precautions listed by the manufacturer: ii. Discuss these findings with your instructor. b. If instructed by your instructor, carry out the inspection procedure. i. Referencing manufacturer s workshop manual, remove and disassemble the wheel and drum assembly. ii. Inspect the serviceability of each component: a. Cam shaft: b. S Cam rollers: Medium Heavy Vehicle Air Brakes 6 2

3 c. Cam shaft bushings, seals spacers, and retainers: d. Brake spider(s): e. Dust shield, anchor pins, and springs 2. Discuss the findings with instructor. 3. If directed by your instructor, carry out this service procedure NATEF Reference Number: 3A2-4 Task Inspect, clean, and adjust air disc brake caliper assemblies (if applicable); determine needed repairs. 3A Referencing manufacturer s workshop manual, service, inspect, and adjust air disc brake assembly: a. List the procedure for servicing the air disc brake caliper assemblies, noting all safety precautions listed by the manufacturer: b. Discuss these findings with your instructor. Medium Heavy Vehicle Air Brakes 6 3

4 2. If instructed by your instructor, carry out the inspection procedure. a. With reference to the manufacturer s workshop manual for precaution and specifications, inspect the air disc brake caliper assemblies component: 3. Discuss the findings with instructor NATEF Reference Number: 3A2-5 Task Inspect and measure brake shoes or pads; perform needed action. 3A Inspect and record brake lining/pad condition and thickness: a. With reference to vehicle manufacturer s workshop manual, research the description and operation of the brake system for this vehicle, including the researching of drum brake diagnostic procedure plus wheel assembly and brake drum(s) removal/installation procedures: i. Discuss these findings with your instructor. ii. If instructed by your instructor, carry out the inspection procedure. iii. Record the following information: a. Maximum drum diameter: in/mm b. Maximum drum out-of-round: in/mm c. Minimum lining thickness (Primary): in/mm d. Minimum lining thickness (Secondary): in/mm iv. Are these measurements within specifications? Yes: No: v. Refit drum and wheel assembly in accordance with manufacturer s specifications. vi. Ensure the wheel lug nuts are torqued to manufacturer s 2007 NATEF Reference Number: 3A2-6 Medium Heavy Vehicle Air Brakes 6 4

5 Task Inspect and measure brake drums or rotors; perform needed action. 3A If fitted with disc brake system, research the description and operation of the brake system for this vehicle, including the researching of disc brake diagnostic procedure plus wheel assembly and disc brake(s) removal/installation procedures. 2. Record the following information: a. Maximum rotor diameter: in/mm b. Maximum rotor out-of-round: in/mm c. Minimum pad thickness: (Outer) in/mm d. Minimum pad thickness (Inner) in/mm 3. Are these measurements within specifications? 4. Refit disc caliper/pad(s) and wheel assembly in accordance with manufacturer s specifications. 5. Ensure the wheel lug nuts are torqued to manufacturer s specification and tightening sequence. 6. Wheel lug nut torque: ft/lbs (N/m) 7. Actual torque: ft/lbs (N/m) 8. Discuss the findings with instructor NATEF Reference Number: 3A2-7 Medium Heavy Vehicle Air Brakes 6 5