Disc run-out check

5. Remove 2 screws securing disc to drive flange.
6. Remove brake disc from drive flange, using jacking screws if necessary.

Refit

CAUTION: Excessive disc run-out can exist after fitting a new disc, with no immediate symptoms being evident whilst driving. The most likely cause of run-out is the presence of contaminants (e.g. rust or paint) or damage to the mating faces of disc and flange, and flange and wheel. Excessive run-out will cause progressive uneven wear of the disc, leading to disc thickness variation, which is the cause of judder. Always ensure that the disc run-out check given here is strictly adhered to.

1. Inspect mating surfaces of new disc and drive flange and clean thoroughly using a wire brush.

NOTE: There is no need to remove the silver protective coating from friction surface of new disc.

2. Fit brake disc to drive flange, fit and tighten screws to 10 Nm.
3. Fit caliper, fit top caliper mounting bolt but do not tighten.

Disc run-out check

4. Mount a dial test indicator to caliper lower mounting using tool 18G 191-9 and tighten bolt. Tighten top mounting bolt.
5. Position dial test indicator probe 10 mm from disc outer edge.
6. Inspect road wheel and flange mating surfaces and remove any contaminants.
7. Fit road wheel(s) and tighten nuts to correct torque. See INFORMATION, Torque wrench settings.
8. Rotate wheel at least one turn and measure disc run-out. Front disc run-out limit = 0.040 mm.

Run-out exceeds limit

9. Mark wheel to stud relationship, remove wheel, again check mating surfaces for contaminants, then refit wheel 90° from previous position and recheck run-out.
10. If run-out is still excessive, move wheel through a further 90° and recheck run-out.
11. If run-out is still excessive, fit a new road wheel.

Run-out within limit

12. Remove dial test indicator and tool 18G 191-9 .
13. Fit caliper lower mounting bolt and tighten both bolts to 108 Nm.
14. Remove stand(s) and lower vehicle.