Tools Required:

J 26900-1  Combimike Micrometer. See Special Tools and Equipment .

1. Reposition and support the caliper and the brake pads. Refer to Brake Pads Replacement - Front  or to Brake Pads Replacement - Rear  as applicable.
2. Clean the brake pad lining contact surfaces of the brake rotor with denatured alcohol or an equivalent brake cleaner.
3. Inspect the braking surfaces of the brake rotor for the following braking surface conditions:
   • Heavy rust and/or pitting

     Use an abrasive disc in order to remove light surface rust.

     Refinish the rotor in order to remove heavy surface rust and/or pitting.

   • Cracks and/or heat spots
   • Excessive blueing discoloration
4. If the braking surfaces of the brake rotor exhibits one or more of the braking surface conditions, refinish or replace the brake rotor.
Fig 1: Measuring Brake Rotor Thickness
Courtesy of GENERAL MOTORS CORP.
5. Use the J 26900-1  or an equivalent micrometer in order to measure any grooves on the rotor braking surface. See Special Tools and Equipment .
6. Compare the groove depth to the following specification:

   Specification:  The maximum groove depth is 1.50 mm (0.059 in).

7. If the groove depth exceeds the specification, or if an excessive amount of scoring is present, refinish or replace the brake rotor. In order to refinish the brake rotor, refer to Brake Rotor Refinishing . In order to replace the brake rotor, refer to Brake Rotor Replacement - Front  or to Brake Rotor Replacement - Rear  as applicable.