If necessary, the working surfaces of the brake discs can be machined. In this case, it is necessary to determine the minimum allowable dimensions of parts after processing from the tables in section 19. After processing, check the parallelism and perpendicularity of the working surfaces relative to the axis of the brake disc.
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 must remove the caliper (see section 17.1.2) and fix the caliper on the car body with a piece of wire without pulling 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 is too tight on the hub, use a hammer with a rubber head.
A protective coating has been applied to the working surfaces of the new brake disc, remove the coating before installation.
When installing the brake disc, carry out the following work:
Check the loose fit of the two clamping sleeves in the front brake disc and front wheel hub or follow the instructions in section 17.1.4. Screw in the caliper mounting bolts and tighten to 115 Nm.
Lubricate the seating surface of the rear wheel hub under the brake disc with long-life grease (Molycote "u") to facilitate the 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. Screw in the caliper mounting bolts and tighten to 50 Nm.
After installation, check the runout of the brake disc. To do this, fix the indicator on the rack so that the tip of the indicator rests parallel to the axis of the hub against the outer edge of the working surface of the brake disc and slowly turn the brake disc (see fig. 252). With a runout of more than 0.12 mm, it is necessary to unscrew the disc mount, turn the disc relative to the hub and close it again. Check that there are no foreign objects on the working surfaces of the brake disc.
Press the brake pedal several times to ensure the correct position of the brake pads relative to the brake disc.