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

Note: Before starting work, refer to the note at the beginning of Section 6 concerning the dangers of asbestos dust.

Removal

1. Chock the front wheels then jack up the rear of the vehicle and support it on axle stands.

2. Remove the appropriate rear wheel, marking its correct fitted position on the drum.

3. Remove the brake drum securing screw then release the handbrake and pull off the drum. If it is tight, collapse the brake shoes by removing the plug in the brake backplate and pushing the handbrake operating lever outwards with a screwdriver (see illustrations).

Removing a brake drum securing screw

Pushing back the handbrake lever

Inspection

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

4. Working carefully, remove all traces of brake dust from the drum, but avoid inhaling the dust as it is injurious to health.

5. Scrub clean the outside of the drum and check it for obvious signs of wear or damage such as cracks around the roadwheel bolt holes; renew the drum if necessary.

6. Examine carefully the inside of the drum.

Light scoring of the friction surface is normal, but if heavy scoring is found the drum must be renewed. It is usual to find a lip on the drum's inboard edge which consists of a mixture of rust and brake dust; this should be scraped away to leave a smooth surface which can be polished with fine (120 to 150 grade) emery paper. If, however, the lip is due to the friction surface being recessed by excessive wear, then the drum must be renewed.

7. If the drum is thought to be excessively worn, or oval, its internal diameter must be measured at several points using an internal micrometer. Take measurements in pairs, the second at right angles to the first, and compare the two to check for signs of ovality.

Provided that it does not enlarge the drum to beyond the specified maximum diameter, it may be possible to have the drum refinished by skimming or grinding; if this is not possible, the drums on both sides must be renewed.

Note that if the drum is to be skimmed, both drums must be refinished to maintain a consistent internal diameter on both sides.

Refitting

8. If a new brake drum is to be installed, use a suitable solvent to remove any preservative coating that may have been applied to its interior.

9. Ensure that the drum and hub flange mating surfaces are clean and dry and remove all traces of corrosion.

10. Make sure that the handbrake lever stop peg is correctly repositioned against the edge of the brake shoe web then locate the drum on the hub. Note that it may be necessary to shorten the adjuster strut length by rotating the strut wheel to allow the drum to pass over the brake shoes.

11. Refit the drum retaining screw and tighten it securely.

12. Adjust the lining to drum clearance by repeatedly applying the footbrake at least fifteen times. Whilst applying the brake have an assistant listen to the rear drums to check that the adjuster strut is functioning correctly; if this is so a clicking sound will be emitted by the strut as the pedal is depressed.

13. With the lining to drum clearance set check and, if necessary, adjust the handbrake.

14. Refit the roadwheel, aligning the marks made on removal, then lower the vehicle to the ground and tighten the wheel bolts to the specified torque setting.