Attention! On vehicles equipped with ABS, this procedure should not be performed as special tools will be required to properly bleed the brakes. Take the vehicle to a service shop or other repair shop that has the appropriate tools and equipment.
Note. Repair if necessary (usually due to a brake fluid leak) Consider all options before starting work. You can often find new or factory remanufactured calipers; in this case, it is very easy to deal with such work. If you decide to restore the calipers yourself, then before starting work, provide yourself with a repair kit.
Withdrawal
1. Remove the stopper from the brake fluid reservoir and pump out 2/3 of the fluid from it with a special tool.
2. Loosen the wheel nuts, raise the front of the vehicle and secure it to the stands. Remove the front wheel.
3. Replace the two wheel nuts with the flat side against the rim to hold the rim in place.
4. Press the piston into the cylinder (see illustration 2.5).
5. Turn away a klyammerny bolt of a brake hose and disconnect a hose. Have a rag handy to wipe up spilled fluid, and wrap a plastic bag tightly around the end of the hose to prevent fluid loss and contamination.
6. Turn away two bolts and remove a support from the car (see illustrations 2.6a and 2.6b).
Repair
7. Refer to section 2 and remove the brake pads from the caliper.
8. Clean the outside of the caliper with brake cleaner or denatured alcohol. Never use gasoline, kerosene or other petroleum-based cleaning solvents. Place the caliper on a clean workbench.
9. Position a block of wood in the caliper as a buffer, then use compressed air to pry the piston out of the caliper (see illustration). Apply just enough air to push the piston out of the cylinder. If the piston comes out, even if a buffer is installed, the piston can be damaged.
3.9. Use compressed air to force the piston out of the cylinder; make sure that your hands or fingers do not get between the piston and caliper!
Attention! Never put your fingers in front of the piston in an attempt to grasp or protect it when compressed air is being supplied - serious injury may result.
10. Carefully remove the boot from the caliper cylinder (see illustration).
3.10. Carefully remove the boot from the casing, being careful not to scratch the surface of the cylinder
11. Using a wooden or plastic tool, remove the piston collar from the groove in the caliper cylinder (see illustration). Metal tools can damage the cylinder.
3.11. To avoid damage to the caliper cylinder or seal groove, it is best to remove the seals with a plastic or wooden tool: 1 - cuff, 2 - plastic strip, 3 - caliper, 4 - groove
12. Remove the caliper bleed valve, then remove and remove the bushings from the caliper lugs. Replace all rubber parts (see illustration).
3.12. Disc brake caliper parts (for the car of release of 1990; others are similar): 1 - guide pin caps, 2 - guide pins, 3 - bushings, 4 - outer brake pad, 5 - wear indicator, 6 - inner brake pad, 7 - protective cover, 8 - piston, 9 - piston collar, 10 - bleed valve, 11 - support
13. Clean remaining parts with brake cleaner or denatured alcohol and dry with compressed air.
14. Carefully inspect the piston for nicks and burrs and check for any loss of coating. If there are surface defects, the parts must be replaced. Check the caliper cylinder in the same way. To remove slight corrosion and stains, it is permissible to use polishing with a fine-grained sandpaper. If the guide pins are damaged or corroded, replace them.
15. Lubricate the piston and cuff with clean brake fluid during assembly. Place the seal in the groove of the caliper cylinder (see illustration).
3.15. Position the collar in the caliper cylinder, being careful not to twist it
16. Lubricate the piston with clean brake fluid, then insert a new boot into the piston groove so that the folds are directed towards the open end of the piston (see illustration).
3.16. Insert the new boot into the grooves of the piston so that the folds point towards the open end of the piston
17. Align the piston in the cylinder, then push hard to seat the piston (see illustration).
3.17. Insert the piston into the caliper cylinder evenly, without distortion
18. Place the boot in the groove of the caliper, then use the drift to set the boot in place (see illustration). Make sure that the dust boot lies flat below the surface of the caliper.
3.18. Using the special gasket tool, seat the boot in the groove of the caliper. If you do not have such a tool, gently tap the circumference of the cover with a mandrel until the boot sits in place
19. Insert the bleed valve.
20. Install new bushings in the holes of the mounting bolts and fill the area between the bushings with the silicone grease included in the repair kit (see illustration). Slide the glasses into the holes in the guide pins.
3.20. Lay silicone grease between the bushings of the guide pins: 1 - guide pin, 2 - glass, 3 - bushing, 4 - caliper body, A - silicone grease
Installation
21. Check that the guide pins are not too heavily corroded.
22. Place a support over a disk and an arm, wrap bolts and tighten them the demanded moment.
23. On 1990 vehicles, make sure that the gap between the caliper and bracket stoppers is between 0.005-0.012 inches (see illustration).
3.23. Measure the gap between the caliper and bracket stoppers at the indicated points (only for 1990 vehicles)
24. Insert the brake hose clamp bolt with new copper washers, then tighten it to the torque specified in the specifications of this chapter. Brakes need to be bled (see section 9).
25. Install the wheels and lower the car.
26. After completing the work, press the brake pedal firmly several times so that the brake pads are installed.