Removing
Attention: It is necessary to replace all brake shoes at the same time, even if only one of them has reached the wear limit! Only use shoes approved by the manufacturer! Never use gasoline or petroleum-based solvents to clean brake system components - use only branded cleaners or methyl alcohol!
Attention: When carrying out work, observe the precautions indicated in Section 1!
Note: It is correct to disassemble the brake mechanisms one by one - the assembled mechanism, if necessary, can be used as a sample when assembling the dismantled one. If both mechanisms are disassembled and it is planned to reinstall the same brake shoes, when removing them, it is necessary to mark the places of their installation. It is not allowed to change the shoes from the right wheel to the left!
Note: It is advisable to simultaneously replace the brake shoes with the replacement of their coupling and guide springs, which, as a result of loads, stretch / sag over time, ceasing to develop the required force, which leads to sticking of the brakes and accelerated wear of the drums.
1. Support the front wheels with wheel chocks, remove both rear wheels and support the rear of the vehicle on jack stands.
2. On Corsa C models, use a screwdriver to remove the protective cap from the wheel hub and loosen the hub nut (see resist. illustration), comply with all requirements given in the relevant section Chapters 8.
10.2. hub nut (1) rear wheel (Corsa C models, drum brake)
Note: The protective cap is damaged during removal and must be replaced during installation.
3. On Corsa Combo models, remove the brake drum lock screw (see resist. illustration).
10.3. Locking screw (2) brake drum (Corsa Combo models)
4. Release the parking brake lever, loosen the parking brake cable if necessary (see Section 17).
5. Remove the brake drum from the axle. If, as a result of prolonged use, any of the discs has become stuck to the wheel hub, use a plastic hammer and knock the disc with light blows.
6. If these attempts are not successful, insert a screwdriver through the hole on the back of the brake shield (see resist. illustration) and press the parking brake lever outward, while the spring takes the brake shoes away from the drum.
10.6. Hole (2) for depressing the parking brake lever
7. Using the special tool Hazet-797, disconnect the upper brake return spring and use a screwdriver to separate the mounting bracket from the front brake shoe (see resist. illustration).
10.7. Coupling (2) and return (3) drum brake springs: 1. Adjusting lever; 4. Mounting bracket
8. Remove the adjusting lever from the brake shoe and disconnect the return spring from it (see illustration 10.7).
9. Slightly spread the brake shoes and remove the adjusting expansion bar installed between them (see resist. illustration).
10.9. Adjusting spreader bar (5): 12. Adjusting gear; 13. Belleville adjusting lever spring
10. Using the special tool KM-346 or Hazet-4963-1, press the plate of the front brake shoe pressure spring (see resist. illustration). Against the force of the spring, rotate the plate and release it from the retainer, while holding the retainer at the back. Remove the plate and spring, remove the retainer. Repeat this operation for the rear shoe.
10.10. Depress clamping spring (6) brake shoe using the KM-346 tool (7)
11. Remove the front brake shoe and disconnect the lower return spring (see resist. illustration).
10.11. Removing the front (8) and rear (11) brake shoe: 9. Lower return spring; 10. Parking brake cable
12. Remove the rear brake shoe and disconnect the drive cable from the parking brake actuating lever (see illustration 10.11).
13. In order to avoid extrusion of the pistons of the wheel brake cylinder, it is necessary to press the pistons with a special spring clip or belt.
Attention: Do not press the brake pedal with the brake pads removed! If the pistons have been squeezed out of the brake cylinder, remove the cylinder and take it to a car service workshop for assembly or replace it. Be careful not to damage the cuffs of the brake cylinder!
Examination
14. Clean all elements of the brake mechanism, observing safety precautions (see section 1).
15. At detection of traces of leak of a brake liquid on cuffs of the wheel brake cylinder replace a corresponding cuff. When installing new cuffs (see resist. illustration) make sure that the pistons are not squeezed out of the cylinder.
10.15. cuffs (1 and 2) wheel brake cylinder - the illustration shows another Opel model
16. Check the condition of the inner working surface of the drum, if necessary, turn the drums into a groove.
Note: Both drums must be machined to the same depth. The compilers of this Guide recommend replacing the brake shoes after turning the drums.
17. If the furrows are too deep or the maximum allowable value of its diameter is exceeded (see Specifications for Chapter 1) replace both brake drums.
18. Small traces of corrosion are eliminated with fine-grained sandpaper. Contact points (see resist. illustration) clean the brake shoes and the rear shield of the brake mechanism with a metal brush and lubricate with a thin layer of special paste (e.g. Liqui Moly) to prevent brake squeal.
10.18. Contact points (indicated by arrows) brake shoes with brake shield
Installation
Note: If necessary, periodically check the correct installation of the elements, comparing them with the location on the second (not filmed) brake mechanism.
19. Check that there are no traces of grease or oil stains on the brake shoes and drum surfaces.
20. Place the parking brake cable in the holder (see resist. illustration).
10.20. Thread the drive cable (1) parking brake holder (2): 3. Guide
21. Attach the drive cable to the rear shoe and install the shoe on the brake shield.
22. Insert the rear shoe spring retainer through the hole on the back of the brake shield into the hole in the brake shoe. Install the spring with the plate, press the plate with a special tool or pliers. Overcoming the force of the spring, turn the plate 90°and fix it.
Note: When performing this operation, you must hold the latch at the back.
23. Attach the lower return spring to both brake shoes, press the lower edge of the front shoe against the guide (see illustration 10.20) and install it on the brake shield. Lubricate the contact spring contact points with heat-resistant paste.
24. Remove the clip/belt from the brake cylinder.
25. Check the ease of movement of the adjusting gear and expander bar (see illustration 10.9). If necessary, disassemble the adjusting assembly and clean it.
26. Lubricate the threads of the adjusting assembly with a thin layer of silicone grease.
27. Pull the adjusting gear back until it stops, then loosen it again a little - the gear should not remain in its extreme position.
28. Install belleville spring (see illustration 10.9) adjustment lever. When replacing the brake shoes, install a new Belleville spring.
29. Spread the upper ends of the brake shoes and insert an adjusting expansion bar between them.
Attention: The expansion bar must be installed with the adjusting gear to the front brake shoe, while the fork of the bar must fit into the corresponding groove of the shoe!
30. Secure the front brake shoe with the pressure spring (see paragraph 22).
31. Install the adjusting lever with return spring on the front brake shoe (see illustration 10.7), secure the lower end of the return spring to the shoe.
32. Insert the mounting bracket (see illustration 10.7) into the retainer and push it into the hole in the shoe. Attach the upper return spring to the rear brake shoe first, and then use the special tool to tension it and attach it to the mounting bracket.
33. Before installing the brake drum, unscrew the adjusting gear of the expansion bar until it stops, and install the brake drum on the axle.
34. Further installation is carried out in the reverse order of removal. When tightening the hub nut, follow the instructions given in Chapter 8.
35. Squeeze the foot brake pedal several times until you feel a firmness of movement - the brake pads are adjacent to the discs and occupy a position corresponding to the state of operation.
36. In the same manner, replace the brake shoes on the opposite wheel.
37. Before starting intensive use, let the brake pads get used a little, for which brake the car several times from a speed of 80 km / h to a speed of 40 km / h by gently pressing the pedal. Then let the brake cool down.
Note: After changing the pads, try to avoid sudden braking as much as possible for about 200 km.
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