Thickness and Parallelism

Raise the rear of the vehicle, and support it with safety stands in the proper locations (see LIFT AND SUPPORT POINTS ).
Remove the rear wheels.
Remove the brake pads (see REAR BRAKE PAD INSPECTION AND REPLACEMENT ).
Using a micrometer (A), measure the disc thickness at eight points, about 45° apart and 10 mm (3/8 in.) in from the outer edge of the brake disc. Replace the brake disc if the smallest measurement is less than the max. refinishing limit.
Brake disc thickness:

Standard: 8.9-9.1 mm (0.35-0.36 in.)

Max. refinishing limit: 8.0 mm (0.31 in.)

Brake disc parallelism: 0.015 mm (0.0006 in.) max.

NOTE: This is the maximum allowable difference between the thickness measurements.

Fig 1: Measuring Disc Thickness
Courtesy of AMERICAN HONDA MOTOR CO., INC.
If the brake disc is beyond the service limit for parallelism, refinish the brake disc with a commercially available on-car brake lathe.
NOTE: If the brake disc is beyond the service limit for refinishing, replace it (see REAR BRAKE DISC REPLACEMENT ).