Drum Brake Adjustment

Special Tools 

CH-21177-A  Drum to Brake Shoe Clearance Gage

1. Ensure the park brake lever is in the fully released position.
2. Remove the rear floor console bolt and raise the rear portion of floor console to gain the access of park brake cable adjusting nut.
3. Release the tension from the park brake cable system at the front cable adjusting nut. Using ONLY HAND TOOLS, loosen the adjusting nut (1) completely to the end of the front cable threaded rod.
   Fig 1: Adjusting Nut

   Courtesy of GENERAL MOTORS COMPANY
4. Raise and support the vehicle. Refer to Vehicle Lifting and Jacking Caution .
5. Remove the tire and wheel assembly. Refer to Tire and Wheel Removal and Installation .
6. Remove the brake drums. Refer to Brake Drum Replacement .
7. Position the CH-21177-A  drum to brake shoe clearance gage to widest point of the brake drum inside diameter.
   Fig 2: Position CH-21177-A Gauge

   Courtesy of GENERAL MOTORS COMPANY
8. Firmly hand tighten the set screw on the CH-21177-A  drum to brake shoe clearance gauge.
9. Remove the CH-21177-A  drum to brake shoe clearance gauge from the brake drum and position it over the corresponding brake shoe assembly at its widest point.
   Fig 3: Remove CH-21177-A Gauge

   Courtesy of GENERAL MOTORS COMPANY
10. While holding the CH-21177-A  drum to brake shoe clearance gauge, insert a proper feeler gauge between one side of the CH-21177-A  drum to brake shoe clearance gauge and the corresponding brake shoe lining.
11. Rotate the brake shoe adjuster screw until the brake shoe linings contact the CH-21177-A  drum to brake shoe clearance gauge and the feeler gauge.

    Specification 

    Brake shoe lining-to-drum clearance: 0.4 - 1.09 mm (0.016 - 0.043 in)

12. Repeat the above steps for the opposite brake drum and brake shoe assembly.
13. Install the brake drums. Refer to Brake Drum Replacement .
14. Adjust the park brake. Refer to Parking Brake Adjustment .
15. Install the rear tire and wheel assemblies. Refer to Tire and Wheel Removal and Installation .
16. Lower the vehicle.
17. Lower the rear portion of floor console and install the rear floor console bolt.