For 1990-2009 cars

Warning: Refer to Brake Dust Warning in the Preface section.

1. Clean the brake pad lining contact surface of the brake rotor with denatured alcohol or an equivalent brake cleaner.
2. Using a micrometer calibrated in ten-thousands of an inch, measure and record the lowest thickness of the brake rotor at four or more points, equally spaced around the rotor.

Ensure that the measurements are only taken within the brake pad lining contact area and that the micrometer is positioned the same distance from the outside edge of the rotor for each measurement.

3. Compare the lowest thickness measurement recorded to the specifications. Refer to Disc Brake Component Specifications.
4. If the lowest thickness measurement of the brake rotor is above the brake rotor minimum thickness specification; the rotor may be refinished, depending upon the surface and wear conditions which may be present.
5. If the lowest thickness measurement of the brake rotor is below the minimum thickness specification; the rotor requires replacement.