GM S-Series Pick-ups and SUV's 1994-1999 Repair Guide

Brake Drums



Brake pads may contain asbestos, which has been determined to be a cancer causing agent. Never clean the brake surfaces with compressed air! Avoid inhaling any dust from any brake surface! When cleaning brake surfaces, use a commercially available brake cleaning fluid.

See Figures 1 and 2

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Fig. Fig. 1: View of a common brake drum used on the S-series pickups

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Fig. Fig. 2: Removing the brake drum from the vehicle

  1. Raise and support the rear of the vehicle safely using jackstands.
  3. Remove the rear tire and wheel assemblies.
  5. Matchmark the drum to the hub or hub studs for installation purposes.
  7. Pull the brake drum from the hub studs. It may by necessary to gently tap the rear edges of the drum using a rubber mallet to start it off the studs.
  9. If the drum will not come off past the shoes, it will be necessary to retract the adjusting screw. Remove the access hole cover from the backing plate and turn the adjuster to retract the linings away from the drum.

To install:

The rear wheel bearings are not adjustable, they are serviced by replacement only. If necessary to replace the rear wheel bearings, please refer to the axle shaft, bearing and seal, removal and installation procedures located in Fuel System of this guide.

  1. If removed, install a rubber adjustment hole cover before reinstalling the drum.
  3. Install the drum in the same position on the hub as removed.
  5. Install the rear tire and wheel assemblies.
  7. Remove the jackstands and carefully lower the vehicle.


Clean all grease, brake fluid, and other contaminants from the brake drum using brake cleaner. Visually check the drum for scoring, cracks, or other damage and replace, if necessary.

Check the drum inner diameter using a brake shoe clearance gauge. There are 2 important specifications when discussing rear drum diameters. The refinish diameter is the maximum diameter to which the drum may be machined. This diameter allows room for drum wear after is has been machined and is returned to service. The discard diameter is the point at which the drum becomes unsafe to use and must be discarded. NEVER refinish a drum to the discard diameter. If after refinishing the drum the diameter is within 0.030 in. (0.76mm) of the discard diameter, the drum MUST be replaced.