Brake Caliper Overhaul (With B9Q/V4U)

REMOVAL PROCEDURE

^ Tools Required
- J 36474 75 mm Boot Seal Installer





1. Raise and support the vehicle. Refer to Vehicle Lift Points in General Information.
2. Remove the tire and wheel assembly.
3. Remove the fluid from the caliper (1).
4. Remove the brake pad. Clean the interior of the caliper with clean shop towels.

CAUTION: Do not place your fingers in front of the piston in order to catch or protect the piston while applying compressed air. This could result in serious injury.

NOTICE: Use just enough air pressure to ease the piston out of the bore. You can damage a blown-out piston even with the padding.

5. Remove the piston.
- Direct compressed air into the caliper fluid inlet.
- Use just enough air pressure to ease the piston out of the bore.





6. Remove the boot using care not to scratch the housing bore.





7. Remove the piston seal with a nonmetal type of tool.





8. Remove the bleeder valve.
9. Use denatured alcohol in order to clean the following parts:
- The bleeder valve
- The caliper bore
- The caliper passages
- The piston
- Use dry, filtered, compressed air to dry the parts and to blow out the passages.

10. Replace any piston with the following conditions:
- Scoring
- Nicked
- Corroded
- Worn
- Damaged chrome plating

11. Replace any caliper bore or seal groove with the following conditions:
- Scoring
- Nicked
- Corroded
- Worn
- Attempt to remove any light corrosion on the caliper bore or seal groove using a crocus cloth.

INSTALLATION PROCEDURE





1. Use clean brake fluid in order to lubricate the following parts:
- The new piston seal
- The caliper bore
- The piston

2. Install the piston seal using care not to twist the seal.





3. Install the boot on the piston.





4. Install the piston and the boot into the caliper bore.
5. Push the piston to the bottom of the bore.





6. Seat the boot housing using J 36474 or J 36475 or J 38453.

NOTICE: Refer to Fastener Notice in Service Precautions.





7. Install the bleeder valve.

Tighten the bleeder valve to 13 Nm (115 lb in).

8. Install the tire and wheel assembly.
9. Lower the vehicle.