Brake Disc Thickness Unevenness Check And Correction

Remove contaminants or corrosion from the brake disc surface.
Use a micrometer to measure the brake disc thickness at minimum eight points which are 10 mm (0.39 inch) inward from its circumference. Then record the measurements.
If the brake disc thickness unevenness (the difference between the maximum and minimum values measured above) is 0.015 mm (0.0006 inch) or less, it is within the standard value.
If the brake disc thickness unevenness exceeds the standard value, grind it according to the procedure below while it is mounted on the vehicle.
NOTE: If it is suspected that the brake disc thickness will become less than the limit value after the grinding, replace the brake disc and check its run-out.

Fig 1: Measuring Brake Disc Thickness Using Micrometer
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
1. Check for wheel bearing looseness in the axial direction (Refer to WHEEL BEARING END PLAY CHECK < Front >, WHEEL BEARING END PLAY CHECK < Rear (FWD) > or WHEEL BEARING END PLAY CHECK < Rear (AWD) >).
  CAUTION:
  - Insert M12 plain washer and then install the adapter as shown before grinding. Failure to use the M12 plain washer will cause the brake disc to be deformed and ground incorrectly.
  - To grind the brake disc, ensure that all the nuts (M12 X 1.5) are tightened evenly and in a diagonal sequence to the specified torque [100 N.m (74 ft-lb)]. Failure to use all the nuts (M12x1.5), excessive or uneven tightening torque will cause the brake disc to deform or judder.
2. Correct the brake disc uneven thickness by grinding it while in place on the vehicle.