Brake Rotor Thickness Measurement

WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.

WARNING:

Refer to Brake Dust Warning .

Courtesy of GENERAL MOTORS COMPANY

Clean the brake pad lining contact surface of the brake rotor with denatured alcohol or an equivalent brake cleaner.
Using a calibrated micrometer measure and record the lowest thickness of the brake rotor at 4 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.
Compare the lowest thickness measurement recorded to the following specifications:
- Specification - Front Brake JH6/JH9
  - Brake rotor minimum allowable thickness after refinishing 37.0 mm (1.457 in)
  - Brake rotor discard thickness 36.50 mm (1.437 in)
- Specification - Rear Brake JH6
  - Brake rotor minimum allowable thickness after refinishing 28.0 mm (1.102 in)
  - Brake rotor discard thickness 27.50 mm (1.083 in)
- Specification - Rear Brake JH9
  - Brake rotor minimum allowable thickness after refinishing 39.0 mm (1.535 in)
  - Brake rotor discard thickness 38.50 mm (1.515 in)
If the lowest thickness measurement of the brake rotor is above the minimum allowable thickness after refinishing specification then the rotor may be refinished, depending upon surface and wear conditions which may be present.
If the lowest thickness measurement of the brake rotor is at or below the minimum allowable thickness after refinishing specification then the rotor may not be refinished.
If the lowest thickness measurement of the brake rotor is at or below the discard thickness specification then the rotor requires replacement.