Removal and installation of the brake caliper piston

Removing

Rotate the axle in the direction of the arrow using a T45 socket wrench.



The locknut will push the piston out of the brake caliper (pic. 6.34).

Remove the piston with protective cap from the brake caliper.



Remove the O-ring using the assembly wedge 3409 (pic. 6.35).

Installation

Surfaces of pistons and sealing rings clean only with alcohol and then dry.

Apply a thin coat of assembly paste G 052 150 A2 to the piston and sealing ring before installation.

Insert the O-ring into the brake caliper.




Slide the outer lip of the seal onto the piston (pic. 6.36).



Turn the lock nut on the axle until the A value of 15 mm is reached (pic. 6.37).



Insert the inner working edge of the protective cap with a wedge into the groove on the brake caliper (pic. 6.38).

Press the piston on the locknut, this is only possible in four positions.

Gently press the piston into the brake caliper while moving the piston.




Push the piston in the brake caliper until it is against the locknut (pic. 6.39).



Carefully rotate the axle clockwise until the nut is fully tightened (pic. 6.40).



Make sure that the protective cap is in contact with the brake caliper all around (pic. 6.41).




Press the piston into the brake caliper by hand (pic. 6.42).

In this case, the outer sealing lip of the protective cap will enter the groove on the piston.

Check valve check

Air must flow through check valve A in the direction of the arrow (pic. 6.43).

In the opposite direction, the valve must remain closed.

Pay attention to the correct mounting position.

Removal and installation of the brake booster pressure sensor

Remove the engine cover.

Remove the vacuum hose with the brake booster pressure sensor from the brake booster.



Unlock clips with pliers 1 (pic. 6.44).

Carefully pry the brake booster pressure sensor 2 downwards.