Disc thickness and parallelism (Brakes)

Disc thickness and parallelism

9. Using a micrometer positioned 10 mm from outer edge of disc, measure thickness of disc at four points. Disc thickness: New = 9.9 - 10.1 mm Service limit = 8.0 mm Maximum thickness variation = 0.015 mm.
10. Renew disc if below service limit.

CAUTION: Brake discs must be renewed in pairs unless one disc requires changing before 1000 miles (1500 km) from new.

NOTE: Brake discs can be refaced using an on car disc lathe providing the disc thickness is sufficiently great to be 1 mm over service limit after machining.

Disc run-out

11. Mount a dial test indicator and position indicator probe 10 mm from outer edge of disc.
12. Rotate disc at least one complete turn and measure disc run-out. Disc run-out limit = 0.10 mm

Run-out exceeds limit

13. Remove 2 bolts securing caliper carrier and remove carrier.
14. Mark disc to flange relationship, and remove disc from drive flange. Clean disc mounting faces, rotate disc 180°and secure with screws. Recheck run-out.