Necessary preliminary work
- Remove WHEELS .
- Remove BRAKE PAD WEAR SENSOR
Lift out retaining spring (1).
Remove cover plug (1).
Unscrew guide bolts (1).
Withdraw brake caliper backwards.
Installation note:
Tightening torque 34 21 4AZ .
Clean guide screws only; do not grease.
Check threads.
Replace all guide bolts which are not in perfect condition.
Overflowing brake fluid will damage the paintwork.
Turn piston back fully with special tool 34 1 050 .
In the event of one-sided brake pad wear, do not change brake pads round.
Remove outer brake pad.
Inner brake pad is located with its spring in the piston.
Clean brake pads.
Do not grease backs of brake pads sleeve.
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 .
Check dust boot (1) for damage and replace if necessary.
Clean contact surface (2) of brake piston with brake cleaner and apply a thin coating of brake pad paste.
Clean contact surfaces (1...2) of brake pad tee heads/brake caliper housing with brake cleaner and apply a thin coating of brake pad paste.
Clean contact surface (3) of brake caliper with brake cleaner and apply a thin coating of brake pad paste.
So as not to damage the surface coating, if possible do not mechanically clean the guide surfaces for the brake pads on the brake caliper mounting bracket. Instead, clean with brake cleaner and apply a thin coating of brake pad paste.
- 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 .
- If necessary, when replacing pads, reset CBS display in accordance with factory specification.