Brake Rotor Thickness Variation Measurement
Brake Rotor Thickness Variation MeasurementTools Required
- J 26900-1 Combimike Micrometer
1. Reposition and support the caliper and the brake pads.
2. Clean the brake pad lining contact surfaces of the brake rotor with denatured alcohol or an equivalent brake cleaner.
3. Use the J26900-1, or the equivalent micrometer, in order to measure the thickness of the brake rotor. Measure the thickness of the rotor at 4 or more points equally spaced around the rotor. Position the J26900-1, or the equivalent, at the same distance from the outside edge of the rotor, in the brake pad lining contact area.
4. Calculate the difference between the thickest and the thinnest measurements in order to determine the amount of thickness variation.
5. Compare the measurements to the following specifications:
Specification
The maximum thickness variation is .....0.013 mm (0.0005 inch).
Important: Brake rotor thickness variation greater than the specification can cause brake pulsation.
6. If the brake rotor thickness variation measurement exceeds the specification, refinish or replace the rotor.
7. If you refinish or replace the rotor, measure the assembled lateral runout (LRO) of the rotor in order to verify the performance of the disc brake system.