Repairing rear brake calipers

• 1 Self-locking hexagon bolt, 35 Nm
  • Renew.
  • When loosening and tightening, counterhold on guide pin.
• 2 Bleeder valve
  • Apply thin coat of assembly paste G 052 150 A2 to thread before screwing in.
• 3 Dust cap
• 4 Guide pin
  • Grease before fitting protective cap.
• 5 Deflector cap
  • Fit onto brake carrier and guide pin.
• 6 Brake carrier with guide pins and protective cap
  • Supplied as genuine part, assembled with sufficient grease on guide pins.
  • If protective caps or guide pins are damaged, install repair kit. Use lubricant sachet supplied to lubricate guide pins.
• 7 Deflector cap
  • Pull on so that outer sealing lip goes over piston.
• 8 Piston with automatic adjustment
  • Removing and installing ⇒ 2.1 Removing and installing rear brake caliper piston.
  • Apply thin coat of assembly paste G 052 150 A2 to piston before installing.
• 9 Sealing ring
  • Removing and installing ⇒ 2.1 Removing and installing rear brake caliper piston.
• 10 Brake caliper with handbrake cable lever
  • If there is a leak at handbrake cable lever, renew brake caliper.
  • Following repair work, pre-bleed brake caliper ⇒ 2.1.3 Pre-bleeding brake caliper.

2.1 Removing and installing rear brake caliper piston

Special tools and workshop equipment required

• Piston compressing tool - T20146-

• Removal wedge - 3409-
• Bleeder bottle

2.1.1 Removing

• Twist piston anti-clockwise out of brake caliper with piston resetting appliance - T20146-.

• Remove seal using wedge 3409.

2.1.2 Installing

The surfaces of the piston and seal must be cleaned only with methylated spirits and then dried.

• Apply a thin coat of assembly paste G 052 150 A2 to piston and seal before inserting.

• Place protective cap with outer sealing lip on piston.

• Insert inner sealing lip into groove in cylinder using wedge 3409.

When doing this, hold piston in front of brake caliper.

• Turn piston to right into brake caliper with piston resetting appliance - T20146-; do not damage protective cap.

2.1.3 Pre-bleeding brake caliper

• Open bleeder valve -arrow A- and, using a commercially available bleeder bottle, fill with brake fluid until bubble-free brake fluid flows from threaded hole of brake hose connection -arrow B-. Close bleeder valve.

Position brake caliper as illustrated to pre-bleed.