Contents: Removal ↓ Installation ↓
The brake disc must be replaced if it is rusty or its remaining thickness has reached the minimum permissible value.
To ensure uniform braking of both wheels, both brake discs must have identically ground surfaces with the same degree of roughness.
Therefore, be sure to replace both brake discs of one axle at the same time.
Caution! When installing new brake discs or after grinding them, new brake pads should also be installed.
Rusty brake discs produce an effect similar to a scraper when braking. This effect is not eliminated even with prolonged braking. In such cases, the brake discs should be replaced.
Removal
Warning! Jacking up a vehicle may pose a risk of injury. It is recommended that you familiarize yourself with the safety precautions for installing a vehicle on jack stands.
1. Mark the direction of rotation of the wheel with an arrow on the sidewall of the tire and loosen the wheel bolts.
2. Jack up the car, place it on jack stands and remove the wheels.
3. Remove the brake pads and caliper.
4. Plug the hole in the wheel brake cylinder with a wooden block, placing it between the piston and the caliper to prevent the piston from slipping out.
5. Secure the removed caliper with wire to the body or to the suspension spring, while preventing the brake hose from twisting or stretching.
6. Unscrew the locking bolt that secures the brake disc.
Caution! The brake disc must not be knocked off the hub with a hammer if it is rusted. Instead, it is recommended to use a rust converter. If the disc cannot be removed in any other way than by knocking it off with a hammer, then it is recommended to replace both the brake disc and the hub. Brake discs should also be replaced with new ones if the appropriate puller was used to remove them.
Installation
In the workshop, brake discs can be checked for runout. The permissible runout of the disc is 0.05 mm. The permissible deviation in disc thickness is 0.01 mm.
The original article is posted on the website VWMANUAL.ru
7. Measure the thickness of the brake disc.
8. Remove rust from the brake disc flange and hub, if necessary.
9. Clean the new brake discs from the protective varnish using nitro solvent.
10. Install the brake disc on the hub and secure it with a bolt with a tightening torque of 4 Nm.
11. Install the brake pads and secure the caliper with bolts.
12. Rear wheel brakes. Adjust the parking brake.
Caution! If the brake hose has been disconnected, reconnect it and bleed the brake system, see the relevant chapter.
13. Install the wheels in accordance with the marks made during removal.
14. Screw in the wheel mounting bolts and lower the vehicle.
15. Tighten the wheel bolts in a cross pattern to a torque of 120 Nm.
Caution: Press the brake pedal all the way down several times until you feel a strong resistance to pressing.
16. Check the brake fluid level in the expansion tank. If necessary, top up the fluid to the maximum mark.
Attention! Make sure that:
- a) the brake hoses are securely connected,
- b) the brake hoses are secured in the holders,
- c) the brake drive bleed nipples are screwed in,
- d) there is a sufficient volume of brake fluid in the expansion tank.
17. Perform a brake system leak test by starting the engine.
To do this, press 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 leaks.
18. Carefully break in the new brake pads. To do this, brake several times, bringing the speed from about 80 km/h to 40 km/h and pressing the brake pedal lightly. Let the brakes cool down in between.
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