Brake Drum Diameter Measurement
WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.
- Clean the brake shoe lining contact surface of the brake drum with denatured alcohol or an equivalent brake cleaner.
- Using a brake drum micrometer calibrated in thousands of an inch, measure and record the largest diameter of the brake drum at four or more points, equally spaced around the drum.
Ensure that the measurements are only taken within the brake shoe lining contact area and that the micrometer is positioned the same distance from the outside edge of the drum for each measurement.
- Compare the largest diameter measurement recorded to the following specifications:
Specification:
- Brake drum maximum allowable diameter after refinishing 251.0 mm (9.882 in).
- Brake drum discard diameter 251.5 mm (9.902 in).
- If the largest diameter measurement of the brake drum is less than the maximum allowable diameter after refinishing specification; the drum may be able to be refinished, depending upon surface and wear conditions which may be present.
- If the largest diameter measurement of the brake drum is equal to or greater than the maximum allowable diameter after resurfacing specification; the drum may not be refinished.
- If the largest diameter measurement of the brake drum is equal to or greater than the discard diameter specification; the drum requires replacement.