Opel Corsa B 1993–2000 Service and Repair Manual: Front brake disc - inspection, removal and refitting

Note: Before starting work, refer to the note at the beginning of Section 4 concerning the dangers of asbestos dust.

Inspection

Note: If either disc requires renewal, both should be renewed at the same time to ensure even and consistent braking.

1. Firmly apply the handbrake, jack up the front of the car and support it on axle stands. Remove the appropriate front roadwheel, marking its correct fitted position on the hub.

2. Slowly rotate the brake disc so that the full area of both sides can be checked; remove the brake pads if better access is required to the inner surface. Light scoring is normal in the area swept by the brake pads, but if heavy scoring is found the disc must be renewed.

3. It is normal to find a lip of rust and brake dust around the disc's perimeter; this can be scraped off if required. If, however, a lip has formed due to excessive wear of the brake pad swept area then the disc's thickness must be measured using a micrometer. Take measurements at several places around the disc at the inside and outside of the pad swept area; if the disc has worn at any point to the specified minimum thickness or less, the disc must be renewed.

4. If the disc is thought to be warped it can be checked for run-out either using a dial gauge mounted on any convenient fixed point, while the disc is slowly rotated, or by using feeler blades to measure (at several points all around the disc) the clearance between the disc and a fixed point such as the caliper mounting bracket. To ensure that the disc is squarely seated on the hub, fit two wheel bolts complete with spacers approximately 10 mm thick and tighten them securely. If the measurements obtained are at the specified maximum or beyond, the disc is excessively warped and must be renewed; however it is worth checking first that the hub bearing is in good condition.

5. Check the disc for cracks, especially around the wheel bolt holes, and any other wear or damage and renew if necessary.

Removal

6. Remove the brake pads.

7. Extract the small retaining screw and then tilt the disc and withdraw it from the hub.

Refitting

8. Refitting is the reverse of the removal procedure, noting the following points.

1. Ensure that the mating surfaces of the disc and hub are clean and flat.
2. If a new disc has been fitted, use a suitable solvent to wipe any preservative coating from the disc before refitting the caliper.
3. On vehicles which are equipped with light alloy roadwheels, a facing sleeve is mounted on the collar of the brake disc.
4. Refit the brake pads.
5. Refit the roadwheel, aligning the marks made on removal, then lower the vehicle to the ground and tighten the roadwheel bolts to the specified torque. On completion, repeatedly depress the brake pedal until normal (non-assisted) pedal pressure returns.