Removing and Installing/Replacing Both Front Brake Discs

34 11 220 - Removing and installing/replacing both front brake discs (S85)





Special tools required:
- 34 1 280





Necessary preliminary tasks:
- Remove wheels
- If necessary, remove and clean brake pads Removing and Installing/Replacing Brake Pads on Both Front Disc Brakes
After completing work, read and comply with notes on braking in new brake discs / brake pads Procedures.





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 .





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).

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!





Unfasten screws (1), remove brake caliper and fasten up.

Note:
Brake hose remains connected.

If the brake hose was pulled from the mounting fixture during removal, make sure it is positively attached when installed!

Installation Note:
Tightening torque 34 11 2AZ .





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

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.

Installation Note:
Thoroughly clean contact surface of brake disc on wheel hub and guide pins (3), remove traces of corrosion if necessary.

Brake disc can only be mounted in one position.

Replace screws.

Tightening torque 34 11 1AZ .

NOTE:
- If brakes pads have been replaced during procedure, reset CBS display in accordance with factory specification, please refer to: Vehicle/ Instrument Panel/ Gauges and Warning Indicators/ Maintenance Required Lamp Indicator/ Service and Repair Service and Repair