Brake Drum Refinishing

CAUTION: Improperly tightened wheel nuts can lead to brake pulsation and rotor damage. In order to avoid expensive brake repairs, evenly tighten the wheel nuts to the proper torque specification.

DO NOT refinish the brake drums in order to correct any of the following complaints:

Brake noise (growl/squeal).
Premature brake lining wear.
Cosmetic or superficial corrosion of the drum braking surface.
Drum discoloration.

Refinish the brake drums ONLY when one or more of the following conditions exist:

Severe scoring of the drum braking surface (groove depth in excess of specification).
Brake pulsation caused by the following:
1. Brake drum out of round (runout in excess of specification).
2. Corrosion or pitting that is deeper than the drum braking surface.

Use a micrometer in order to measure the largest diameter of the brake drum. If the largest diameter of the brake drum exceeds the brake drum maximum refinish diameter, DO NOT refinish the brake drum. Replace the brake drum.
Use the Rotor/Drum Flange Resurfacing Kit (J-41013) in order to THOROUGHLY clean the rust from the brake drum flange.
Refinish the brake drum.
After machining the brake drum, use 120 grit aluminum oxide sandpaper in order to create a non-directional braking surface.
Clean the braking surfaces with GM P/N 12377981 or equivalent brake parts cleaner.