34 21 812 Overhauling left or right rear brake caliper (brake caliper removed): Installation:

Only clean guide screws; do not grease. Check guide bolts, replace if necessary.

Tightening torque, refer to REAR BRAKE .

Dismantle brake caliper and remove brake linings.

Before installing springs (4), press out brake lining completely.

Fig 1: Identifying Springs

Press out piston with compressed air applied through connection bore.

To protect the piston, fit a protective plate (hardwood, hard felt or similar) in the caliper duct.

Fig 2: Pressing Out Piston With Compressed Air Applied Through Connection Bore

Check guide sleeves (5), installing guide sleeves from repair kit if necessary.

Repair kit for guide sleeve, refer to BMW Parts Service.

Fig 3: Checking Guide Sleeves

Remove sealing ring carefully with a plastic needle.

Fig 4: Removing Sealing Ring Carefully With A Plastic Needle

Clean cylinder bores and parts with alcohol and dry with compressed air.

Inspect cylinder bore, piston and flange surfaces thoroughly for damage. Machining of cylinders and pistons is not permitted.

Apply light coat of ATE brake-cylinder paste to cylinder bore, piston, dust cover and sealing cover.

Install sealing cover in rear annular groove of cylinder bore.

Fig 1: Installing Sealing Cover In Rear Annular Groove Of Cylinder Bore

First fit dust cover to piston, insert sealing bulge in front groove of cylinder bore and press in piston using a hardwood board.