If the brake disc is damaged, it is necessary to check the runout of the outer working surface in the assembled state using an indicator.
To remove the brake disc, you need to remove the caliper (see section 17.1.2) and use a piece of wire to secure the caliper to the car body without stretching the brake hose. Check the position of the parking brake pads in the rear brake disc.
The brake disc can be removed separately or together with the rear wheel hub as described in section 17.1.4. If the brake disc fits tightly on the hub, use a hammer with a rubber striker.
The working surfaces of the new brake disc are coated with a protective coating; remove the coating before installation.
When installing the brake disc, perform the following work:
Check that the two clamping bushings fit freely in the front brake disc and the front wheel hub, or follow the instructions in section 17.1.4. Tighten the caliper mounting bolts to 115 Nm.
Lubricate the rear wheel hub seating surface under the brake disc with long-life grease (Molycote "u") to facilitate subsequent removal of the brake disc. Install the pin in the wheel hub so that it fits freely into the hole in the brake disc. Tighten the caliper mounting bolts and tighten to 50 Nm.
After installation, check the runout of the brake disc. To do this, attach the indicator to the stand so that the tip of the indicator rests parallel to the hub axis against the outer edge of the working surface of the brake disc and slowly turn the brake disc (see fig. 252). If the runout is more than 0.12 mm, it is necessary to unscrew the disk fastening, turn the disk relative to the hub and close it again. Check for foreign objects on the working surfaces of the brake disk.
Press the brake pedal several times to ensure the correct position of the brake pads relative to the brake disc.