34 11 000 Removing and installing/replacing brake pads on both front disc brakes
Special tools required:
- Due to the increased strain on the brake discs, we recommend that you also replace the brake discs when fitting this brake pad.
- It is absolutely essential to replace the brake discs if cracked ≥ 13 mm even before the brake pad is worn.
Necessary preliminary tasks:
- Remove wheels
- Remove BRAKE PAD WEAR SENSOR
Observe SAFETY INSTRUCTIONS on raising the vehicle.
Lever out retaining spring (1) in direction of arrow towards rear.
Installation:
Attach retaining spring (1) first at top and bottom and then allow retaining lug (2) to engage in recess of brake caliper housing.
Remove plastic plugs (1).
Left:
Pull brake pad wear sensor (1) towards rear out of pad.
Release guide screws (2) with special tool 34 1 080 . Withdraw brake caliper backwards.
Installation:
Only clean guide screws; do not grease.
Check threads.
Replace all guide screws which are not in perfect condition.
Tightening torque 34 11 3AZ .
Press back brake pads and piston with special tool 34 6 320.
- Pay attention to brake fluid level in expansion tank; brake fluid that spills over will damage paintwork.
Press brake pads inwards and remove.
The two brake pads are seated with a spring in the piston or in the brake caliper housing and must not be mixed up.
In the event of one-sided brake pad wear, do not change brake pads round.
Observe MINIMUM THICKNESS OF BRAKE PADS .
Clean brake pads.
Do not apply grease to brake pad backplate.
The outer brake pads gradually need to be changed as well.
The previous version (A) with retaining spring (1) is replaced by brake pads of version (B) without retaining spring!
The use of pad sets of version (A) with retaining spring continues to be permissible!
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 .
New brake pads may only be installed if the brake disc thickness is greater than or equal to the MINIMUM BRAKE DISC THICKNESS (MIN TH) (not incl. M vehicles).
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).
The minimum brake disc thickness is configured in such a way that it lasts the life of a further set of brake pads (does not apply to M vehicles and perforated brake discs).
Check dust sleeve (1) for damage and replace if necessary.
Clean contact face (2) of brake piston and apply a thin coating of anti-squeak compound.
Clean mounting faces (1) and (2) of brake pad hammer heads/brake caliper housing and coat with anti-squeak compound.
Clean mounting face (3) of brake caliper and apply a thin coating of anti-squeak compound.
Clean brake caliper holder at hammerhead guides and apply a thin coating of anti-squeak compound.
Refer to BRAKES - OPERATING FLUIDS .
- Fully depress brake pedal several times so that brake pads contact brake discs.
- When installing new brake pads at front and rear axles, brake fluid level must be brought up to "MAX" marking.
- Read and comply with notes on BREAKING IN NEW BRAKE DISCS / BRAKE PADS .
- When replacing pads, reset CBS display in accordance with MAINTENANCE REMINDER LIGHT RESET PROCEDURES .
The fault memory entry must be deleted. The vacuum pressure sensor only has to be replaced if the fault is entered repeatedly.