Rear Brake Calipers (C38), Servicing

Rear brake caliper, servicing





Notes:
^ When carrying out repairs install all of the parts supplied in the repair kit.
^ New brake calipers are filled with brake fluid and are pre-bled.
^ Apply a thin coat of brake cylinder paste G 052 150 A2 to brake cylinders, pistons and seals.

1. Self- locking bolts 35 Nm
- Always replace
- When loosening and tightening counter- hold on guide pin
2. Brake caliper housing with parking brake cable lever
- Replace if leaking at parking brake cable lever
- Pre-bleed caliper housing after repairing see Fig. 6
3. Bleeder valve
- Apply thin coat of brake cylinder paste G 052 1 50 A2 to threads before screwing in
4. Protective cap
- Install onto bleeder valve
5. Seal
- Use 3409 wedge to remove see Fig. 2
6. Piston with automatic adjustment
- Unscrewing from brake caliper housing see Fig. 1
- Screwing into brake caliper housing see Fig. 5
- Apply thin coat of brake cylinder paste G 052 150 A2 before installing
7. Guide pins
- Grease before pulling on dust seal
8. Dust seal
- Install so that outer sealing lip goes over piston see Fig. 3
- Install so that inner sealing lip enters groove in brake caliper housing see Fig. 4
9. Dust seal
- Pull onto brake carrier and guide pin
10. Brake carrier with guide pins and dust seal
- Supplied as pre-assembled replacement part with sufficient grease on guide pins
- If dust seals or guide pins are damaged, install repair kit.
- Use grease packet supplied to lubricate guide pins

Rear brake caliper piston, removing and installing





Special tools and equipment
- 3272 reset tool
- 3272/1 support plate
- 3409 wedge

Removing





Fig. 1 Unscrewing piston from brake caliper housing
- Remove piston by turning threaded spindle -A- counter clockwise and knurled section -B- clockwise.





Fig. 2 Removing seal using 3409 wedge

Installing
- Use only appropriate solvent to clean surfaces of piston and protective seal, then dry.
- Apply thin coat of brake cylinder paste G 052 150 A2 to piston and protective seal before installing.





Fig. 3 Pulling dust seal on with outer sealing lip on piston





Fig. 4 Inserting inner sealing lip of dust seal using 3409 wedge

Note: Hold piston in front of caliper housing for this procedure.





Fig. 5 Screwing piston into brake caliper housing until stop
- Install piston by turning threaded spindle -A- clockwise and knurled section -B- counter-clockwise.

Note: Outer sealing lip of dust seal will then engage in piston groove.





Fig. 6 Pre-bleeding brake caliper
- Open bleeder valve and fill with brake fluid using standard bleeder bottle until brake fluid flows out of threaded hole (brake hose connection) without bubbles. Close bleeder valve.

Note: Position brake caliper as shown during pre-bleed procedure.