Brake Rotor Thickness Measurement (Without RPO LNF)
WARNING: This page is about a different car, the 2010 Pontiac G5 and 2010 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
WARNING:
Refer to Brake Dust Warning
.
- If the inboard friction surface of the brake rotor is not accessible, reposition and support the caliper with the brake pads. Refer to Front Disc Brake Pads Replacement (Without RPO LNF) and/or Rear Disc Brake Pads Replacement , if equipped.
- Clean the friction surfaces of the brake rotor with denatured alcohol, or an equivalent approved brake cleaner.
- Using a micrometer calibrated in thousanths-of-a-millimeter, or ten-thousanths-of-an-inch, measure and record the thickness of the brake rotor at 4 or more points, evenly spaced around the rotor.
Ensure that the measurements are only taken within the friction surfaces and that the micrometer is positioned the same distance from the outer edge of the rotor, about 13 mm (1/2 in), for each measurement.
- Compare the lowest thickness measurement recorded to the following specifications:
Specification - Front J41/JM4
- Brake rotor minimum allowable thickness after refinishing: 22.75 mm (0.896 in)
- Brake rotor discard thickness: 22.0 mm (0.87 in)
Specification - Front JL9
- Brake rotor minimum allowable thickness after refinishing: 23.0 mm (0.906 in)
- Brake rotor discard thickness: 22.8 mm (0.898 in)
Specification - Rear
- Brake rotor minimum allowable thickness after refinishing: 12.0 mm (0.472 in)
- Brake rotor discard thickness: 11.8 mm (0.465 in)
- If the lowest thickness measurement of the brake rotor is above the minimum allowable thickness after refinishing specification, the rotor may be able to 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, the rotor may not be refinished.
- If the lowest thickness measurement of the brake rotor is at or below the discard thickness specification, the rotor requires replacement.