Brake Drum

Refinishing

Minor scores on a brake drum (1126) can be removed with sandpaper. Do not refinish brake drums to remove score marks. A drum surface which is highly polished can cause the brake to lock up. This polished condition should be removed either with sandpaper or by refinishing the drum. A brake drum that is out-of-round sufficiently enough to cause vehicle vibration or noise when braking, should be refinished. Remove only enough stock to true-up the brake drum. Brake drum maximum inside diameter is shown on each brake drum. If the maximum inside diameter shown on the brake drum is exceeded either through wear or refinishing, the brake drum must be replaced.

Check the inside diameter of the brake drum with Brake Adjustment Gauge D81L-1103-A or Rotunda Brake Drum Micrometer 010-00010 or equivalent.

After a brake drum is refinished, wipe the refinished surface with a cloth soaked in clean denatured alcohol. If one brake drum is refinished, the opposite brake drum on the same axle should also be refinished to the same diameter.

Service Limits

Brake drum maximum diameter is molded into the rim of the brake drum. The brake drum may be machined enough to correct scoring but only up to the MAX. DIA. dimension. If, after machining, the brake drum inside braking surface diameter exceeds the specification, it must be discarded.