GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2009 🢒 TopKick C-Series (Conventional) C4/C5 🢒 Brakes 🢒 Air Drums 🢒 Air Brake Automatic Slack Adjuster Replacement

Air Brake Automatic Slack Adjuster Replacement Arvin-Meritor

Removal Procedure

    Important: For unit repair information on the Arvin-Meritor® air brake automatic slack adjuster contact the Field Support Center at 1-800-535-5560.

  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 Air Brake Reservoir Draining .
  4. Raise and support the vehicle with safety stands. Refer to Lifting and Jacking the Vehicle .

    5. 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: 201809 Size: SH
  6. Remove the retainers.
  7. Remove the air brake chamber clevis pins.

    8. Object Number: 201765 Size: SH
  8. Fully release the air brake automatic slack adjuster using the following steps:
    9. 8.1. Disengage the pawl with a screwdriver.
    8.2. Turn the air brake automatic slack adjuster adjusting nut until the air brake automatic slack adjuster is free from the air brake chamber clevis.
    8.3. Release the pawl so that the pawl snaps into engagement.

    Object Number: 201813 Size: SH
  9. Remove the camshaft snap ring.

    10. Object Number: 261832 Size: MH
  10. Remove the camshaft washer(s) (9).
  11. Remove the air brake automatic slack adjuster (4).

    12. Object Number: 201816 Size: SH
  12. Check the air brake automatic slack adjuster adjusting nut torque using the following steps:
    13. 12.1. Use a pound/inch torque wrench in order to rotate the air brake automatic slack adjuster adjusting nut counterclockwise.
    12.2. Turn the air brake automatic slack adjuster gear 360 degrees, 22  rotations of the air brake automatic slack adjuster adjusting nut. The torque must remain less than 4.5 N·m (40 lb in). Replace the air brake automatic slack adjuster if the torque specification is exceeded.

    Object Number: 201809 Size: SH
  13. Inspect the air brake chamber clevis pins for wear or damage.

    14. Replace the air brake chamber clevis pins if necessary.


    Object Number: 261832 Size: MH
  14. Measure the bushing in the arm of the air brake automatic slack adjuster (4).

    15. Replace the bushings if the diameter exceeds 13.5 mm (0.531 in).

Installation Procedure

    Object Number: 261834 Size: MH
  1. Install the air brake automatic slack adjuster to the camshaft (12).
  2. Install the camshaft washers (13).

    3. Object Number: 201813 Size: SH
  3. Install the camshaft snap ring.

    4. Object Number: 201765 Size: SH
  4. Disengage the pawl assembly with a screwdriver.

    5. Object Number: 201817 Size: SH
  5. Turn the slack adjuster adjusting nut until the slack adjuster arm is properly aligned with the holes in the clevis.
  6. Release the pawl so that the pawl snaps into engagement.

    7. Object Number: 201804 Size: SH
  7. Align the marks made on the air brake automatic slack adjuster and the camshaft.
  8. Fully release the air brake automatic slack adjuster.
  9. Install the air brake chamber clevis pins.
  10. Install the NEW retainers.
  11. Adjust the brakes. Refer to Air Drum Brake Adjustment .
  12. Remove the safety stands and lower the vehicle. Refer to Lifting and Jacking the Vehicle .
  13. Uncage the rear air brake chambers. Refer to Caging the Rear Air Brake Chamber .
  14. Check for proper brake operation.
  15. Apply the parking brake.
  16. Remove the wheel blocks.