Brake Rotor Thickness Variation Measurement (With ZL1 (Front))

Brake Rotor Thickness Variation Measurement (With ZL1 (Front))

Warning: Refer to Brake Dust Warning Brake Dust Warning.


Note: Due to the floating design of the brake rotor, the front brake rotor cannot be refinished. If the front brake rotor is found to exceed the specification, it must be replaced.

Note: Do not remove the brake rotor from the wheel hub.

1. If the inboard friction surface of the brake rotor is not accessible, reposition and support the brake caliper with the brake pads. Refer to Front Brake Rotor Replacement (LFX) Front Brake Rotor ReplacementFront Brake Rotor Replacement (L99, LS3) Front Brake Rotor ReplacementFront Brake Rotor Replacement (LSA) Front Brake Rotor Replacement.

2. Clean the friction surfaces of the brake rotor with denatured alcohol, or an equivalent approved brake cleaner.




3. Using a micrometer 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 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.

4. Calculate the difference between the highest and lowest thickness measurements recorded to obtain the amount of thickness variation.

5. Compare the thickness variation measurement to the following specification:

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

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

6. If the brake rotor thickness variation measurement exceeds the specification, the rotor requires replacement.