Withdrawal
Attention! If the brake pads are to be reinstalled for later use, they should be marked before removal. Swapping the pads from the right wheel to the left and vice versa or swapping the outer and inner pads is not allowed. Be sure to change all brake pads at the same time, even if only one of them has reached the wear limit.
1. Mark the position of the rear wheels on the hub with paint. This will allow the assembly to set the balanced wheel in its original position.
2. Loosen the wheel bolts. The vehicle must be on wheels during this operation.
3. Install the car on the goats and, having unscrewed the bolts, remove the rear wheels.
4. Unscrew the lower and upper caliper mounting bolts, holding the guide pins with a wrench from turning (see illustration).
6.4. Unscrew the lower and upper caliper mounting bolts, holding the guide pins with a wrench from turning
5. Remove a support and, without disconnecting a brake hose from it, fix it on a body. Mount the caliper on the body so as not to stretch the brake hose under the weight of the caliper.
6. Remove the brake pads from the guide.
Installation
Attention! With the brake pads removed, do not press the brake pedal. In this case, when you press the pedal, the piston will be squeezed out of the brake cylinder. If the piston is still out of the cylinder, remove the caliper and take it and the piston to a workshop for repair.
7. Clean (degrease) landing and guiding surfaces of the brake pads in the caliper with a rag soaked in alcohol. Do not use solvents containing mineral oils or sharp-edged tools.
Attention! Use only alcohol to clean the brake mechanism.
8. Before installing the pads, check the brake disc for the absence of grooves by running your hand over it. Brake discs with grooved surface should be replaced with new ones.
9. Measure the brake disc thickness. Replace the disc whose remaining thickness has reached the minimum allowable thickness, see the appropriate chapter.
10. Check up a condition of a protective cap of the piston of the brake cylinder. Replace a damaged and cracked cap immediately, because dirt penetrating through a damaged cap quickly leads to depressurization of the caliper. In this case, the brake caliper must be removed and taken to a workshop for overhaul.
Attention! When the piston is depressed, the brake fluid is squeezed out of the wheel brake cylinder into the expansion tank. Keep an eye on the level of brake fluid in the expansion tank and, if necessary, take it away to prevent it from splashing out.
Attention! To withdraw brake fluid from the expansion tank, use a siphon or a plastic bottle that is not destroyed by brake fluid. Do not use regular drinking water bottles! Brake fluid is poisonous and must never be sucked out by mouth through a hose. Use a siphon. And after replacing the brake pads, the level of brake fluid in the reservoir should not exceed the maximum mark, because. when heated, it expands. Leaking brake fluid flows down the master cylinder, destroying its protective lacquer layer and causing corrosion.
11. Screw the piston into the cavity of the wheel cylinder using a special tool AUDI-3272 until it stops. Protrusion on the rod of the device (see arrow in illustration) should be in contact with the caliper. Screw in the piston by turning the tool rod to the right by the handle. If the piston is difficult to enter, then when screwing in the piston, turn the tool rod by the flats with a wrench.
6.11. Screw the piston into the cylinder using the special tool AUDI-3272
Attention! The piston of the wheel brake cylinder of the rear wheel must not be pressed in with a special pressing tool or with a wooden hammer handle. In this case, the parking brake mechanism is damaged. When removing and installing brake pads or when disassembling a wheel cylinder, it should be taken into account that the cylinder has a device for adjusting the working gap between the brake pads and the piston. The main element of the device is a threaded regulator, along which the piston rod is displaced as the brake linings wear, thereby maintaining the required clearance between the brake shoes and the piston. As the brake pads wear out, at some point the rod does not reach the cylinder piston. The gap adjustment device just prevents this situation, «lengthening» stock as needed. For this reason, when replacing worn brake linings with new ones, the wheel cylinder piston cannot simply be pressed back into its original position. Its push-up is performed with rotational movements.
If there is no special tool for screwing in the piston, turn a rectangular bar to the desired size and insert it into the grooves on the piston of the brake cylinder, and then screw the piston into the cylinder by pressing it.
12. Install both new brake pads in the guide (see arrows in illustration), by removing the protective foil.
6.12. Install both new brake pads in the guide (see arrows)
13. Reinstall the caliper and secure it with new self-locking bolts with a tightening torque of 35 Nm, keeping the guide pins from turning.
Attention! The repair kit includes four self-locking hex head bolts that are designed to replace the old caliper mounting bolts.
14. Establish back wheels according to the marks put at removal.
15. Screw in bolts of fastening of wheels and lower the car on wheels.
16. Tighten the bolts in a cross pattern with a torque of 120 Nm. Attention! Squeeze out a few times a brake pedal against the stop, the strong resistance to pressing is not felt yet. When this action is performed, the brake pads are centered and they self-adjust to the working position.
17. Check up level of a brake liquid in a broad tank. If necessary, add fluid up to the maximum mark.
18. Adjust parking brake (see relevant chapter).
Attention! Make sure that:
- brake hoses are securely connected and fixed in holders;
- fittings for bleeding the brake actuator are tightened and closed with caps;
- there is enough brake fluid in the expansion tank.
19. Start the engine and perform a leak test on the brake system. To do this, depress the brake pedal with a force of 200-300 N (20-30 kg) and hold it for about 10 seconds. The pressure in the system and, accordingly, the resistance of the brake pedal, should not decrease. Check all connections for tightness.
20. Carry out a test drive and break in new brake pads. To do this, slow down several times, bringing the speed from about 80 km / h to 40 km / h and lightly pressing the brake pedal. Let the brakes cool down in between.
Attention! New brake pads should be worn in. Therefore, before driving at least 200 km with new brake pads, avoid unnecessary braking until the car comes to a complete stop.
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