Brake Rotor Thickness Variation Measurement
WARNING: This page is about a different car, the 2017 Chevrolet Spark. However, it is still accessible from the selected car via links, so may be relevant.
WARNING:
Refer to Brake Dust Warning
.
NOTE:
Any disc brake rotor that exhibits thickness variation exceeding the maximum acceptable level must be refinished or replaced. Thickness variation exceeding the maximum acceptable level can cause brake pulsation.
- 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 .
- Clean the friction surfaces of the brake rotor with denatured alcohol or an equivalent approved 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 spaced around the brake rotor.
Make sure 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 brake rotor, about 13 mm (1/2 in), for each measurement.
- Calculate the difference between the highest and lowest thickness measurements recorded to obtain the amount of thickness variation.
- Compare the thickness variation measurement to the specification. Refer to Disc Brake Component Specifications .NOTE: Whenever a brake rotor is refinished or replaced, the assembled lateral runout (LRO) of the brake rotor must be measured to make sure optimum performance of the disc brakes.
- If the brake rotor thickness variation measurement exceeds the specification, the brake rotor requires refinishing or replacement.