Warning: When replacing disc brake pads, you should replace both front wheels at the same time, and never replace new pads on just one wheel, as this will result in uneven braking. Dust generated by brake pad wear may contain asbestos, which is hazardous to health. Never blow out brakes with compressed air or inhale dust. Wear a respirator when working on brakes. Do not use gasoline or petroleum based solvents to clean brakes. Use only brake cleaning fluid or methylated spirits. Do not allow brake fluid, oil or lubricants to come into contact with the brake pads or discs.
1. After applying the parking brake, loosen the front wheel nuts, jack up the front of the vehicle and place it on supports. Please remember that on cars produced before 1992 (with six-stud wheels) the wheel nuts on the left side have left-hand threads and are unscrewed clockwise. Remove the front wheels.
2. Cars with independent front suspension have front brakes with floating calipers. An earlier version of this type of caliper is used on models with non-ventilated discs, while a later version is used on models with ventilated discs. Both types of calipers are virtually identical in operation, but there are significant differences in some caliper maintenance and repair procedures. Therefore, it is important to correctly determine which type is installed on your car in order to follow the correct procedures and, when purchasing spare parts, to buy those that will fit.
3. All vehicles with dependent suspension have rigidly mounted calipers with two or four pistons installed opposite each other.
Floating calipers
Cars with non-ventilated discs
4. After removing the plastic covers, unscrew the two guide pin bolts that secure the caliper to the pad guide. Separate the caliper from the brake pads and guide and set it aside, taking care not to stretch the brake hose (see Figure 4.4, a-g).
Figure 4.4,a. Remove the plastic covers.
Figure 4.4, b....unscrew the bolts of the upper and lower guide pins.
Figure 4.4,c.... and remove the bolts.
Figure 4.4d....then remove the caliper.
5. Remove the brake pads from the guide. If you are not going to replace them with new ones, store them separately and mark them: they are identical, but when reinstalled they must be installed in their original positions (see figure 4.5).
Figure 4.5. Separating the inner and outer brake pads of the caliper from the guide.
6. Remove dust and dirt from the caliper and pistons, but do not inhale the dust - it is hazardous to your health. Inspect the protective caps around the pistons for damage or brake fluid leaks. If such faults are detected, the caliper must be disassembled in accordance with Section 6.
7. When installing new brake pads, the caliper pistons must be pushed back into their sleeves, as the new pads are thicker. Use a U-clamp or a proprietary compression tool to compress the pistons, but remember that as you force the pistons back into their barrels, the fluid level in the master cylinder reservoir will rise and may overflow. To avoid this, drain a small amount of liquid from the tank. If brake fluid spills onto the body, hoses or adjacent components in the engine compartment, wipe it dry without delay.
8. Make sure the pads and disc are clean before installation. Remove the protective paper wrapping from the new pads. When installing old pads, make sure they are installed correctly as marked when they were removed.
9. Place the inner and outer brake pads into the caliper guide.
10. Reinstall the piston housing and insert the two guide pin bolts. Tighten the bolts to the specified torque and cover them with plastic caps.
11. Repeat the procedure on the other front brake.
12. Before lowering the vehicle, ensure that the fluid level in the master cylinder reservoir does not exceed the maximum mark and, if necessary, top up the reservoir with the specified type of fluid. Press the brake pedal a few times to position the pads against the disc, then recheck the fluid level in the reservoir and top up again if necessary.
13. Install the wheels and lower the car to the ground. Tighten the wheel nuts to the specified torque.
14. To properly seat new brake pads and allow them to achieve full effectiveness, a break-in period is necessary (approximately 160 km), during which, as far as possible, heavy loads and sudden braking should be avoided.
Cars with ventilated discs
15. Using a small screwdriver, remove the cap from the lower guide pin bolt (see Figure 4.15).
Figure 4.15. After removing the plastic cap from the caliper guide pin bolt...
16. After unscrewing the lower guide pin bolt, turn the caliper up to access the pads (see Figure 4.16). If necessary, tie the body in this position using a thread or wire.
Figure 4.16. ... remove the guide pin bolt and rotate the caliper upward to access the pads.
17. Remove the brake pads from the guide. If you are not going to replace them with new ones, store them separately and mark them: they are identical, but when reinstalled they must be installed strictly in their original positions.
18. If installing new pads, remove the pad spring inside the caliper using a screwdriver (see figure 4.18).
Figure 4.18. Brake pad spring removed from the caliper. The photo shows the correct orientation of the spring, which must be observed during installation.
19. Remove dust and dirt from the caliper and pistons, but do not inhale the dust - it is dangerous to your health. Inspect the piston caps for damage or brake fluid leaks, which will require complete disassembly of the caliper in accordance with Section 6.
20. When installing new brake pads, the caliper pistons must be pushed back into their sleeves, as the new pads are thicker. Use a horseshoe clamp or a patented compression tool to compress the pistons (see Figure 4.20), but remember that when the pistons are pressed back into their sleeves, the fluid level in the master cylinder reservoir will rise and may go beyond the limits. To avoid this, drain a small amount of liquid from the tank. If brake fluid spills onto the body, hoses or adjacent components in the engine compartment, wipe it dry without delay.
Figure 4.20. Using a special compression tool to move the pistons back into the caliper.
21. Make sure the pads and disc are clean before installation. Remove the protective paper wrapping from the new pads. When installing old pads, make sure they are installed correctly as marked when they were removed.
22. Install the new brake pad spring into the caliper (see Figure 4.22).
Figure 4.22. Installing a new spring into the caliper.
23. Insert the brake pads into the caliper pad guide (see Figure 4.23).
Figure 4.23. Install the brake pads into their places in the guide.
24. With the caliper lowered into place, install the guide pin bolt, tightening it to the specified torque. Cover the bolt head with a plastic cap.
25. Repeat the procedure on the other front brake.
26. Before lowering the vehicle to the ground, make sure that the fluid level in the brake master cylinder reservoir does not exceed the maximum mark; if necessary, top up with the specified type of fluid. Press the brake pedal a few times to position the pads against the disc, then recheck the fluid level in the reservoir and top up again if necessary.
27. Install the wheels and lower the car to the ground. Tighten the wheel nuts to the specified torque.
28. To properly seat new brake pads and allow them to achieve full effectiveness, a break-in period is necessary (approximately 160 km), during which, as far as possible, heavy loads and sudden braking should be avoided.
Fixed support with opposite cylinders
29. While releasing the brake shoe guide clamps one by one, grasp the corresponding shoe retainers with your fingers and remove them. Then remove the clamps (see Figure 4.29).
Figure 4.29. Removing the guide clamps and pins.
30. Once you have noted the location of each brake pad, pull them out of the caliper, using a pair of pliers if necessary (see Figure 4.30).
Figure 4.30. Removing brake pads from the caliper.
31. Remove dust and dirt from the caliper and pistons, but do not inhale the dust - it is hazardous to your health. Inspect the protective caps around the pistons for damage or brake fluid leaks, which if found will require complete disassembly of the caliper in accordance with Section 6.
32. When installing new brake pads, the caliper pistons must be pushed back into their sleeves, as the new pads are thicker. To do this, use a piston expander or a screwdriver inserted between the disc and the pistons, or a flat rod with a soft gasket, but remember that when pressing the pistons back into their sleeves, the fluid level in the master cylinder reservoir will increase and may go beyond the permissible limits. To avoid this, drain some liquid. If brake fluid spills onto bodywork, hoses, or adjacent components in the engine compartment, wipe it dry immediately.
33. Make sure the pads and disc are clean before installation. Remove the protective paper wrapping from the new pads. When installing old pads, make sure they are installed correctly as marked when they were removed.
34. Place the brake pads into the caliper.
35. Install the guide clips and brake shoe pins.
36. Repeat the procedure on the other front brake.
37. Before lowering the vehicle to the ground, ensure that the fluid level in the brake master cylinder reservoir does not exceed the maximum mark and, if necessary, top up with the specified type of fluid. Press the brake pedal a few times to position the pads against the disc, then recheck the fluid level in the reservoir and top up again if necessary.
38. Install the wheels and lower the vehicle to the ground. Tighten the wheel nuts to the specified torque. regulated by the specification.
39. To properly seat new brake pads and allow them to achieve full effectiveness, a break-in period is necessary (approximately 160 km), during which, as far as possible, heavy loads and sudden braking should be avoided.