Brake Rotor Surface and Wear Inspection
Brake Rotor Surface and Wear Inspection^ Tools Required
- J 8001 Dial Indicator set or equivalent
1. Raise and support the vehicle. Refer to Vehicle Lifting.
2. Remove the tire and wheel assemblies.
3. Clean the braking friction surfaces of the brake rotor with denatured alcohol or an equivalent approved brake cleaner.
4. Inspect the braking surfaces of the brake rotor for the following braking surface conditions:
^ Heavy rust and/or pitting
^ Cracks and/or heat spots
^ Excessive bluing discoloration
5. Light surface rust can be removed with an abrasive disc. If the braking surfaces of the brake rotor exhibits one or more of the remaining conditions then the brake rotor requires refinishing or replacement.
6. Using a calibrated micrometer measure and record the thickness variation of the brake rotor at 4 or more points around the rotor.
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 each measurement.
7. Compare the thickness variation recorded to the following specification:
Specification
Brake rotor maximum allowable thickness variation 0.025 mm (0.001 inch).
8. If the brake rotor thickness variation exceeds the specification, the brake rotor requires refinishing.
9. Using the micrometer measure and record any grooves present on the rotor braking surface.
10. Compare the groove/scoring depth recorded to the following specification:
Specification
Brake rotor maximum allowable scoring 1.50 mm (0.059 inch).
11. If the brake rotor scoring depth exceeds the specification or if an excessive amount of scoring is present, the brake rotor requires refinishing.
Important: Ensure the wheel bearings are properly adjusted before proceeding with the following steps.
12. Mount a dial indicator, J8001 or equivalent and position the indicator button so it contacts the brake rotor at a 90 degree angle, approximately 13 mm (0.5 inch) from the rotor's outer edge.
13. Measure and record the lateral runout of the brake rotor.
13.1. Rotate the rotor until the lowest reading is displayed on the indicator dial, then zero the dial.
13.2. Rotate the rotor until the highest reading is displayed on the dial.
14. Compare the lateral runout reading to the following specification:
Specification
Brake rotor maximum allowable lateral runout 0.05 mm (0.002 inch).
15. If the brake rotor lateral runout exceeds the specification, the brake rotor requires refinishing.