GM Service Manual Online
For 1990-2009 cars only

Removal Procedure

  1. Block the wheels.
  2. Cage the rear air brake chambers. Refer to Caging the Rear Air Brake Chamber .
  3. Drain all air reservoirs. Refer to Draining Reservoirs in Air Brakes.

  4. Object Number: 201804  Size: SH
  5. Mark the position of the air brake automatic slack adjuster to the camshaft by drawing a straight line on both parts.

  6. Object Number: 201846  Size: SH
  7. Remove the front air brake chamber clevis pin retainers.
  8. Remove the front air brake chamber clevis pins.

  9. Object Number: 201809  Size: SH
  10. Remove the rear air brake chamber clevis pin retainers.
  11. Remove the rear air brake chamber clevis pins.

  12. Object Number: 201765  Size: SH
  13. Fully release the air brake automatic slack adjuster.
  14. Disengage the pawl with a screwdriver.
  15. Turn the air brake automatic slack adjuster adjusting nut until the air brake automatic slack adjuster is free from the air brake chamber clevis.
  16. Release the pawl so that the pawl snaps into engagement.

  17. Object Number: 209228  Size: SH
  18. Loosen the jam nut.
  19. Remove the air brake chamber clevis and the jam nut.
  20. Inspect the air brake chamber pushrod for damage. Overhaul or replace the service brake chamber assembly if damaged.

Installation Procedure


    Object Number: 209228  Size: SH
  1. Loosely assemble the jam nut and the air brake chamber clevis to the air brake chamber pushrod.
  2. Adjust the air brake chamber clevis by turning the air brake chamber clevis clockwise in order to decrease the distance and counterclockwise in order to increase the distance.

  3. Object Number: 201873  Size: SH
  4. Adjust the front air brake chamber clevis to 72.0 mm (2.83 in) from the mounting surface of the air brake chamber to the center of the air brake chamber clevis pin mounting hole.

  5. Object Number: 201877  Size: SH
  6. Adjust the rear air brake chamber clevis to 68.5 mm (2.69 in) from the mounting surface of the rear air brake chamber to the center of the air brake chamber clevis pin mounting hole.

  7. Object Number: 209228  Size: SH

    Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  8. Install the front air brake chamber clevis jam nut (type 16 air brake chamber).
  9. Tighten

        • Tighten the front air brake chamber clevis jam nut (type 16 air brake chamber) to 45 N·m (33 lb ft).
        • Tighten the front air brake chamber clevis jam nut (types 20 and 24 air brake chamber) to 78 N·m (57 lb ft).
        • Tighten the rear air brake chamber clevis jam nut to 78 N·m (57 lb ft).

    Object Number: 201765  Size: SH
  10. Fully release the air brake automatic slack adjuster.
  11. Disengage the pawl with a screwdriver.
  12. Turn the air brake automatic slack adjuster adjusting nut until the air brake automatic slack adjuster arm is properly aligned with the holes in the air brake chamber clevis.
  13. Release the pawl so that the pawl snaps into engagement.

  14. Object Number: 201809  Size: SH
  15. Install the air brake chamber clevis pins.
  16. Install the new air brake chamber clevis pin retainers.
  17. Adjust the brakes. Refer to Air Drum Brake Adjustment .
  18. Start the engine.
  19. Charge the system to the air compressor governor valve cut-out point.
  20. Stop the engine.
  21. Uncage the rear air brake chamber assemblies. Refer to Caging the Rear Air Brake Chamber .
  22. Check for proper brake operation.
  23. Set the parking brake.
  24. Remove the wheel blocks.