Front brake disc - examination, removal and refitting
Examination
1 Raise the front of the vehicle and remove the roadwheel.
2 Examine the surface of the disc. If it is deeply grooved or scored or if any small cracks are evident, it must either be refinished or renewed. Any refinishing must not reduce the thickness of the disc to below the specified minimum. Light scoring on a brake disc is normal and should be ignored.
3 If disc distortion is suspected, the disc can be checked for run-out using a dial gauge or feeler blades located between its face and a fixed point as the disc is rotated.
Checking the brake disc run-out using a dial gauge
4 Where run-out exceeds the specified figure, renew the disc.
Removal
5 To remove a disc, unbolt the caliper, withdraw it and tie it up to the suspension strut to avoid strain on the flexible hose.
6 Extract the small disc retaining screw and pull the disc from the hub.
Refitting
7 If a new disc is being installed, clean its surfaces free from preservative before refitting the caliper. It will also be necessary to depress the piston and inner brake pad a small amount to accommodate the new thicker disc when assembling.
8 Refit the disc, its retaining screw, the caliper and the roadwheel and lower the vehicle to the floor.