Front Brake Caliper, Servicing
Double piston brake caliper, front, repairing (S4/S6 models)CAUTION: When repairing, use all the parts in repair kit.
Note: Coat brake cylinder, piston and piston seal lightly with brake assembly lube.
1. Dust cap
Install on bleeder valve
2. Bleeder valve
Coat threads lightly with brake assembly lube
3. Brake caliper housing
CAUTION: Do not separate the halves of the caliper housing (with internal serrations) from each other If the protective cap for the guide bolts is damaged, replace the brake caliper
4. Piston seal
Remove with screwdriver ~ Fig. 2
Install carefully by hand
5. Piston
Force out of brake caliper housing with compressed air ~ Fig 1
WARNING: Risk of accident! Apply pressure gradually. Guard against sudden release of the piston.
Place wooden board into the recess of the caliper housing to catch the pistons so that they are not damaged ~ Fig. 1.
Piston diameter: 42.8 mm (1.685 in)
Installing ~ Fig. 3, Fig. 4 and Fig. 5
Coat piston with brake assembly lube
6. Piston outer seal
Installing ~ Fig. 4
Fig. 1 Pressing pistons out of brake caliper housing individually with compressed air
WARNING: Risk of accident! Apply pressure gradually. Guard against sudden release of the piston.
Place wooden board into the recess of the caliper housing to catch the pistons so that they are not damaged.
- Force piston -b- out of the caliper bore.
- Place wooden block -a- in housing so piston is not damaged.
Note: Only one piston at a time can be pressed out, hold the other piston in the brake caliper housing with piston reset device.
Fig. 2 Removing piston seals
Fig. 3 Installing piston outer seal on piston
Fig. 4 Installing piston outer seal lip into cylinder groove
Note: Hold piston in front of brake caliper housing.
Fig. 5 Installing piston
Note: Install piston in bore by hand and then install brake pad -a- in the piston before pressing into brake caliper housing.
CAUTION: When pressing in, the seal lip of the piston outer seal must spring into the groove on the piston.