Brake Rotor Thickness Measurement
CAUTION:
Avoid grinding brake linings, sanding brake linings or cleaning wheel brake parts with a dry brush or with compressed air, when servicing wheel brake parts. Some models or aftermarket brake parts may contain asbestos fibers which can become airborne in dust. Breathing dust with asbestos fibers may cause serious bodily harm. Use a water-dampened cloth in order to remove any dust on brake parts. Equipment is available commercially in order to perform this washing function. These wet methods prevent fibers from becoming airborne.
- If the inboard friction surface of the brake rotor is not accessible, reposition and support the caliper with the brake pads. See BRAKE PADS under REMOVAL & INSTALLATION.
- 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. See Fig 1. 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 about 1/2" (13 mm), for each measurement.
- Compare the lowest thickness measurement recorded to the rotor minimum allowable thickness after refinishing and the rotor discard thickness specifications. See DISC BRAKE SPECIFICATIONS .
- 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. See BRAKE ROTOR REFINISHING under OVERHAUL.
- 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 then the rotor requires replacement. See BRAKE ROTOR under REMOVAL & INSTALLATION.