34 33 000 Removing and installing or replacing brake booster (brake servo)

Necessary preliminary work: 

• Read and comply with GENERAL INFORMATION .
• Remove the WIPER MOUNTING BRACKET .
• Remove the TANDEM BRAKE MASTER CYLINDER .

Removal: 

Remove screws (1) and remove footwell air duct (2).

Courtesy of BMW OF NORTH AMERICA, INC.

Detach retaining clip (1) from brake pedal, disengage and pull out retaining bolt (2).

Courtesy of BMW OF NORTH AMERICA, INC.

Unscrew nuts (1).

Courtesy of BMW OF NORTH AMERICA, INC.

Release screws (1).

Release battery housing (2) from bracket and remove.

Release control unit (3) from bracket.

Detach wiring harness (4) from battery tray (5).

Remove battery tray (5).

Courtesy of BMW OF NORTH AMERICA, INC.

Unclip brake lines (1) from holder (2).

Courtesy of BMW OF NORTH AMERICA, INC.

Pull non-return valve (1) in direction of arrow out of brake booster.

Courtesy of BMW OF NORTH AMERICA, INC.

Attention! 

Do not use any force when removing and installing the brake booster; the brake booster can be damaged under certain circumstances.

Brake lines must not be bent.

Carefully pull brake servo (1) out of bulkhead and tilt out in upward direction.

Courtesy of BMW OF NORTH AMERICA, INC.

Preparation for installation: 

Replace seal (1).

Parts:  Gasket

Courtesy of BMW OF NORTH AMERICA, INC.

Installation: 

Carefully insert brake servo (1) into bulkhead.

Courtesy of BMW OF NORTH AMERICA, INC.

Installation note: 

Replace seal for vacuum line/ check valve (1) in the brake booster. 

Install non-return valve (1) in direction of arrow into brake booster.

Courtesy of BMW OF NORTH AMERICA, INC.

Clip brake lines (1) into bracket (2).

Courtesy of BMW OF NORTH AMERICA, INC.

Install battery tray (5).

Tighten down screws (1).

Install wiring harness (4) on battery tray (5).

Insert control unit (3) in bracket.

Insert battery housing (2) into bracket.

Courtesy of BMW OF NORTH AMERICA, INC.

Insert nuts (1) and tighten.

Replace self-locking nuts.

Parts:  Self-locking nuts

Tightening torque, refer to: 34 33 1AZ .

Courtesy of BMW OF NORTH AMERICA, INC.

Grease retaining bolt (1) with lubricating grease NBU 12K (part number: 83 23 9 407 810;  see BMW Service Operating Fluids). Refer to: BRAKES - OPERATING FLUIDS

Install retaining bolt (1) through brake pedal.

Mount retaining clip (2) on retaining bolt.

Replace retaining clip (2).

Parts:  Retaining clip

Courtesy of BMW OF NORTH AMERICA, INC.

Install footwell air duct (2).

Insert screws (1) and tighten.

Courtesy of BMW OF NORTH AMERICA, INC.

Required follow-up work: 

• Remove the WIPER MOUNTING BRACKET .
• Install the TANDEM BRAKE MASTER CYLINDER .
• Install left footwell trim.