Warning: On models equipped with ABS, disconnect the battery before opening the hydraulic system and do not reconnect it until the bleeding operation is complete and the reserve tank is filled with fluid. If this is not done, air may enter the ABS hydraulic system. To remove this, specialized diagnostic equipment will be required - you will have to contact the dealer for help.
Note: Before you begin, please refer to the warnings at the beginning of the paragraphs 2 and 4, containing information about the harmfulness of brake fluid and asbestos dust.
Removal
1. Apply the handbrake and lift the front of the car with a jack, install safety supports. Remove the corresponding wheel. When removing the wheels, tighten one bolt into the hubs so that the brake discs do not shift relative to the hub.
2. Remove the cap from the brake fluid reserve reservoir and place a circle of polyethylene film underneath it to seal the cap tightly and minimize brake fluid loss when unscrewing the hose. Alternatively, you can clamp the hose with a clamp or a parrot wrench.
3. If necessary, disconnect the wiring from the brake pad wear sensor, disconnect the sensor from the connector on the caliper bracket.
4. Clean the area around the tube connection. Loosen the hose connection nut. Remove the mounting bracket from the caliper and move the tube away. Plug the tube and the hole in the caliper to prevent dirt from getting into the system and brake fluid from spilling. Immediately wash off any spilled fluid with cold water.
5. On models with ATE/Teves calipers, carefully pry up the retaining spring with a screwdriver. Remove the plugs from the guide bushings and unscrew the guide mounting bolts.
6. On models with Lucas calipers, hold the guide pins with an open-end wrench and loosen and remove the bolts that secure them
7. Remove the caliper, freeing it from the wear sensor wiring (if any). Remove the inner brake shoe from the piston and the outer shoe from the caliper bracket. Remove the bolts and the caliper bracket.
Repair
8. On the workbench, clean and wash the caliper from dirt and rust using brake cleaning fluid, being careful not to inhale the dust to avoid harm to your health.
9. Remove the piston from the caliper body and remove the dust cover.
10. Using a blunt tool such as an old plastic knife, remove the hydraulic seal from the cylinder, being very careful not to damage the cylinder surface.
11. Wash all components thoroughly using only a special liquid - methyl or isopropyl alcohol. Do not use mineral solvents such as kerosene or gasoline for washing, they are aggressive for rubber hydraulic parts. Dry the components immediately with compressed air or a lint-free cloth. Blow out the channels with compressed air.
12. Replace damaged and worn parts. Pay special attention to the surface of the cylinder and piston. If there are scratches, abrasions or corrosion on them, the parts must be replaced. Check the condition of the guide pins and the corresponding bores in the caliper. The pins should not be damaged and should move easily enough in the bores, but not dangle in them. If in doubt, replace the defective parts.
13. If you plan to install the old caliper back, then purchase the necessary parts for it; the dealer has them in various combinations. All rubber seals and dust boots of the caliper must be replaced - an axiom. Never use old seals and dust boots.
14. Before assembly, make sure that all components are absolutely clean and dry (fig. 8.14, a, 6).
Fig. 8.14, a. Components of the Tevee/ATE front caliper: 1. Plug; 2. Guide pins (bolts); 3. Bleeding nipple; 4. Cap; 5. Caliper (bracket); 6. Brake shoe retaining spring; 7. Guide bushings; 8. Caliper mounting bracket; 9. Piston seal; 10. Piston; 11. Dust cover
Fig. 8.14, b. Components of the Lucas front caliper: 1. Cap; 2. Bleeding nipple; 3. Caliper (bracket); 4. Guide rail mounting bolts; 5. Piston seal; 6. Piston; 7. Dust cover; 8. Caliper mounting bracket
15. Immerse the piston and new seal in clean brake fluid and lubricate the inner surface of the cylinder with it.
16. Install the piston seal into the cylinder groove using only finger force - using tools may damage the seal.
17. Install the new dust boot on the piston. Insert the piston into the cylinder. Gently press the piston into the cylinder, turning it slightly so that it enters without tilting. Press the piston completely into the cylinder until the outer edge of the dust boot fits into the groove on the caliper.
18. If replacing guide bushings, push the old bushings out of the housing and press in the new ones.
19. Before installation, fill the caliper with fresh brake fluid by unscrewing the bleed nipple and bleeding it until bubbles stop coming out of the nipple.
Installation
20. Bolt the caliper bracket to the steering knuckle using new bolts and tightening them to the specified torque (fig. 8.20, a-c). Install the brake pads as described in paragraph 4. Place the bracket over the pads.
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21. Tighten the guide pin mounting bolts to the specified torque. Install the plugs on the bushings.
Note: On Lucas models, install new pin retaining bolts.
22. Attach the brake pipe and mounting bracket to the caliper. Tighten the bracket mounting bolt and pipe union nut to the specified torques.
23. Install the shoe retaining spring.
24. Properly route the wiring into the lower plug loop and connect the brake pad wear sensor wiring connector to the caliper bracket.
25. Remove the clamp or plastic circle (what was installed) and bleed the hydraulic system as described in paragraph 2. Please note that it may be sufficient to pump only one disturbed circuit.
26. Install the wheel, lower the vehicle to the ground and tighten the wheel bolts to the specified torque as described in Chapter 1A or 1B.