Brake Disc Thickness Check

1. Using a micrometer, measure disc thickness at eight positions, approximately 45° apart and 10 mm (0.39 inch) in from the outer edge of the disc.
Brake disc thickness Standard value:
24 mm (0.94 inch)
20 mm (0.79 inch)
Limit:
22.4 mm (0.88 inch)
18.4 mm (0.72 inch)
Thickness variation (at least 8 positions)
The difference between any thickness measurements should not be more than 0.015 mm (0.0006 inch).
2. If the disc is beyond the limits for thickness, remove it and install a new one. If thickness variation exceeds the specification, replace the brake disc or turn rotor with an on the car type brake lathe ("Accuturn-8750" or equivalent). Be sure to follow the exact brake lathe manufacturer instructions.