Brake Rotor Thickness Measurement (J56 Front)

Brake Rotor Thickness Measurement (J56 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 be at or below the minimum specification, it must be replaced.

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

1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle Service and Repair.

2. Remove the tire and wheel assembly. Refer to Tire and Wheel Removal and Installation Service and Repair.

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




4. 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 four 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.

5. Compare the lowest thickness measurement recorded specifications. Refer to Disc Brake Component Specifications Disc Brake Component Specifications.

6. If the lowest thickness measurement of the brake rotor is above the brake rotor discard thickness specification, the rotor may be able to be reused, depending upon surface and wear conditions which may be present.

7. If the lowest thickness measurement of the brake rotor is at or below the brake rotor discard thickness specification, the rotor requires replacement.

8. Install the tire and wheel assembly. Refer to Tire and Wheel Removal and Installation Service and Repair.