Parking Brake Adjustment

Special Tools 

CH-21177-A  Drum-to-Brake Shoe Clearance Gauge

For equivalent regional tools, refer to Special Tools .

1. Apply and fully release the park brake.
2. Verify that the park brake pedal releases completely.
   • Turn ON the ignition. Verify the BRAKE indicator lamp is off.
   • If the BRAKE indicator lamp is on, ensure the park brake pedal is in release mode and has fully returned to the stop. Remove the slack in the front park brake cable by pulling downward on the cable.
3. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .
4. Remove the rear tire and wheel assemblies. Refer to Tire and Wheel Removal and Installation .
Fig 1: Parking Brake Intermediate Cable Adjustment Nut
Courtesy of GENERAL MOTORS COMPANY
5. Loosen the locknut (1) at the park brake cable equalizer to relieve tension on the park brake system.
6. Remove the rear brake rotors. Refer to Rear Brake Rotor Replacement .
7. Using appropriate cleaning equipment, clean the parking brake components of any accumulated dust.
Fig 2: Drum-to-Brake Shoe Clearance Gauge
Courtesy of GENERAL MOTORS COMPANY
8. Set the CH-21177-A  Drum-to-Brake Shoe Clearance Gauge (1) inside of the park brake drum at the widest point.
   • Place the contacts on the tool to the widest point of the drum.
   • Tighten the set screw on the tool to ensure the proper measurement when removing the tool from the drum.
Fig 3: Drum-To-Brake Shoe Clearance Gauge
Courtesy of GENERAL MOTORS COMPANY
9. Position the CH-21177-A  Drum-to-Brake Shoe Clearance Gauge (1) over the park brake shoe at the widest point.
10. Turn the adjuster screw until the park brake shoe just contacts the CH-21177-A  Drum-to-Brake Shoe Clearance Gauge.
11. Repeat steps 8-10 for the opposite side.
12. Install the rear brake rotors. Refer to Rear Brake Rotor Replacement .
13. Install the rear tire and wheel assemblies. Refer to Tire and Wheel Removal and Installation .
Fig 4: Parking Brake Intermediate Cable Adjustment Nut
Courtesy of GENERAL MOTORS COMPANY
14. While holding the intermediate parking brake cable stationary, tighten the parking brake intermediate cable locknut (1) until all slack is removed from the parking brake cables.
15. Apply a minimum of 538 N (120 lb) of force to the parking brake control module pedal.
16. Release the parking brake control module pedal.
17. Verify the parking brake control module pedal releases completely and the red BRAKE warning indicator is not illuminated.
18. Apply 480 N (108 lb) of force to the parking brake control module pedal.
19. Verify the parking brake control module pedal is within the specification range when the force is applied.

    Specification 

    Number of pedal clicks when 480 N (108 lb) of force is applied: 6-9 clicks

20. Lower the vehicle to curb height.
21. Apply the park brake, then inspect for rotation of the rear wheels. If the rear wheels rotate during this inspection, then readjust the park brake shoes.
22. Release the park brake. Verify the rear wheels rotate freely.
23. Lower the vehicle.