34 21 320 Removing and installing or replacing both rear brake discs (S85)

Special tools required:

34 1 280

Necessary preliminary tasks:

Remove wheels . See 36 10 300 REMOVING OR INSTALLING FRONT OR REAR WHEEL
If necessary, remove and clean brake linings . After completing work, read and comply with notes on braking in new brake discs/brake pads .

After completing work:

Adjust parking brake.
Read and comply with notes on braking in new brake discs / brake pads .

Check minimum brake disc thickness:

Position special tool 34 1 280 at three measuring points in area (1) and measure.
Compare measurement result and lowest value with setpoint value. See 21 - REAR BRAKES .

Fig 1: Position Special Tool 34 1 280 At Three Measuring Points In Area (1) And Measure

Courtesy of BMW OF NORTH AMERICA, INC.

IMPORTANT:

In the case of M vehicles and perforated brake discs, new brake pads may only be installed if the brake disc thickness is greater than the minimum brake disc thickness (MIN TH). See 21 - REAR BRAKES .

Brake discs may only be replaced in pairs (on each axle).

If the brake discs are replaced, you must also fit new brake pads.

The brake discs of M models are tied to the direction of travel.

The uneven part number denotes the left brake disc, the even part number the right brake disc!

Release screws (1), remove brake caliper and tie up.

Fig 2: Release Screws (1), Remove Brake Caliper And Tie Up

Courtesy of BMW OF NORTH AMERICA, INC.

NOTE: Brake hose remains connected.

Installation: Tightening torque, see 34 21 3AZ in 34 21 REAR BRAKE .

Release screws (1) and remove brake disc (2).

Fig 3: Release Screws (1) And Remove Brake Disc (2)

Courtesy of BMW OF NORTH AMERICA, INC.

IMPORTANT: To release brake disc: Do not under any circumstances strike friction ring with a hammer or similar! If necessary, carefully tap on base of brake disc chamber with a rubber mallet.

Make sure contact surfaces between wheel hub and brake disc are absolutely clean. Replace screws. Tightening torque, see 34 21 1AZ in 34 21 REAR BRAKE .