Chevrolet Equinox Service Manual: Brake Rotor Thickness Variation Measurement Disc Brakes Brake Rotors

Warning:Refer toBrake Dust Warning.

Note:Any disc brake rotor that exhibits thickness variation exceeding the maximum acceptablelevel must be refinished or replaced. Thickness variation exceeding the maximum acceptablelevel can cause brake pulsation.

If the inboard friction surface of the brake rotor is not accessible, reposition andsupport the caliper with the brake pads. Refer toFront Disc Brake Pads Replacementand/orRear Disc Brake Pads Replacement.Clean the friction surfaces of the brake rotor with denatured alcohol, or an equivalentapproved brake cleaner.

Using a micrometer-(1)-calibrated in thousandths-of-a-millimeter, or ten-thousandths-of-an-inch,measure and record the thickness of the brake rotor at 4 or more points, evenly spacedaround the rotor.

Ensure that the measurements are only taken within the friction surfaces and thatthe micrometer is positioned the same distance from the outer edge of the rotor, about13-mm (½-in), for each measurement.

Calculate the difference between the highest and lowest thickness measurements recordedto obtain the amount of thickness variation.Compare the thickness variation measurement to the following specification:

Specification

Brake rotor maximum allowable thickness variation: 0.025-mm (0.001-in)

Note:Whenever a brake rotor is refinished or replaced, the assembled lateral runout (LRO)of the rotor must be measured to ensure optimum performance of the disc brakes.

If the brake rotor thickness variation measurement exceeds the specification, therotor requires refinishing or replacement.