Drum Brake Adjustment

WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Special Tools

J 21177-A Drum to Brake Shoe Clearance Gauge. See Special Tools .
J 42450-A Wheel Hub Resurfacing Kit

WARNING: Refer to Brake Dust Warning .

NOTE: This procedure must be performed after replacing the brake shoes or whenever the brake shoes have been removed.

Fig 1: Removing Brake Drum

Courtesy of GENERAL MOTORS CORP.

Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .
Remove the rear tire and wheel. Refer to Tire and Wheel Removal and Installation .
Disable the park brake cable automatic adjuster. Refer to Parking Brake Cable Adjuster Disabling .
Remove the brake shoe adjuster access plug from the backing plate.
Insert a thin bladed tool (2) through the adjuster access hole in the backing plate until it contacts the adjuster lever (4).
Push the adjuster lever away from the adjuster screw (1).
Using a suitable tool (3), rotate the adjuster screw upward.
Remove the brake drum. Refer to Brake Drum Replacement .

Fig 2: Cleaning Mating Surface Of Rear Axle Flange

Courtesy of GENERAL MOTORS CORP.

Using the J 42450-A (1), clean the mating surface of the rear axle flange.

Fig 3: Measuring Brake Drum

Courtesy of GENERAL MOTORS CORP.

Using the J 21177-A (1), measure the inside diameter of the brake drum. See Special Tools .

Fig 4: Adjusting Rear Brake Shoes

Courtesy of GENERAL MOTORS CORP.

With the set screw (1) locked, place the opposite side of the J 21177-A over the brake shoes. See Special Tools .
Rotate the brake shoe adjuster screw until the brake shoes just contact the J 21177-A . See Special Tools .
Inspect the clearance between the brake shoes and the brake drum.
Specification: Approximately 0.76 mm (0.030 in)
Install the brake drum. Refer to Brake Drum Replacement .
Enable the park brake cable automatic adjuster. Refer to Parking Brake Cable Adjuster Enabling .
If necessary, adjust the park brake cable tension. Refer to Parking Brake Adjustment (1500 Drum Brake) or Parking Brake Adjustment (1500 Disc Brake) or Parking Brake Adjustment (2500/3500 SRW) or Parking Brake Adjustment (3500 DRW) .
Install the tire and wheel. Refer to Tire and Wheel Removal and Installation .
Lower the vehicle.