Overhauling Left or Right Rear Brake Caliper (Brake Caliper Removed)
34 21 812 - Overhauling left or right rear brake caliper (brake caliper removed)
Note:
Use repair kit,
refer to BMW Parts Service.
Take off plastic caps (1).
Unscrew guide bolts (2).
Installation:
Only clean guide screws; do not grease. Check guide bolts, replace if necessary.
Tightening torque 34 21 5AZ 34 21 Rear Brake.
Dismantle brake caliper and remove brake linings.
Installation:
Press brake lining fully outwards and insert spring (4).
Warning!
Risk of injury!
In the following work step, large forces occur at the brake caliper piston (up to more than 2800 N!).
Important!
Do not grip piston with fingers - risk of trapping!
To protect piston, place a protective plate (e.g. hard wood or hard felt) in calliper recess.
Carefully force piston out through connection bore with compressed air.
Check guide sleeves (5), fitting repair-kit guide sleeve if necessary.
Remove sealing ring carefully with a plastic needle.
Clean cylinder bores and parts with alcohol and dry with compressed air.
Thoroughly inspect cylinder bore, piston and flange surfaces. Machining of cylinders and pistons is not permitted.
Installation:
Apply a light coat of Ate brake cylinder paste to cylinder bore, piston and sealing sleeve,
Refer to BMW Service Operating Fluids.
Install sealing cover in rear annular groove of cylinder bore.
Insert dust sleeve in front annular groove and press into annular groove over entire diameter.
Installation:
The area between the dust sleeve and the brake calliper housing must be kept dry. This area must not come into contact with Ate brake cylinder paste or brake fluid so as to ensure that the dust sleeve is perfectly seated.
Take up brake piston with a commercially available extension and socket and gently press onto dust sleeve.
Blow up sleeve with compressed air (max. 3 bar). Sleeve jumps over brake piston.
Installation:
Coat dust sleeve and brake piston with brake fluid to facilitate installation of dust sleeve.