BMW X3 (F25) Service & Repair Manual: Brake booster

• Removing and installing brake booster vacuum pressure sensor
• Removing and installing or replacing brake booster
• Replacing vacuum hose for brake booster (N63)
• Replacing vacuum hose for brake booster (diesel fuel)
• Replacing vacuum hose for brake booster (petrol)

Removing and installing brake booster vacuum pressure sensor

Detach service opening (1).

Disconnect plug connection (1) at vacuum sensor.

Carefully remove vacuum sensor (2) from brake booster in direction of arrow.

Installation note: Check seal in brake booster and replace if necessary.

Removing and installing or replacing brake booster

Necessary preliminary work:

• Read and comply with GENERAL INFORMATION.
• Remove left footwell trim .
• Remove BRAKE MASTER CYLINDER.
• Remove WIPER MOUNTING BRACKET .

Detach retaining clip (1) on brake pedal.

Pull out locking pin.

Unscrew nuts (2).

Installation note: Replace self-locking nuts.

Release brake lines (1) from holder on bulkhead.

If necessary disconnect plug connection of vacuum sensor.

Pull vacuum line (2) out of brake booster.

Installation note: Check gasket, replace if necessary.

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

Brake lines must not be bent.

Carefully pull brake booster (3) out of bulkhead and tilt out.

Installation note:

Make sure seal (2) is present and correctly seated.

The protective film on the connection of the vacuum line must be removed when replacing the brake booster!

Replacing vacuum hose for brake booster (N63)

IMPORTANT: Before beginning work, fully press the brake pedal several times to reduce the vacuum pressure in the brake servo. This makes it easier to remove the vacuum hose.

Vacuum hose and non-return valve are welded together and are replaced together as a single unit.

Necessary preliminary tasks:

• Read and comply with GENERAL INFORMATION.
• Remove partition wall, units compartment

Pull off partition wall seal upper part (1) in direction of arrow.

Remove non-return valve (2) from brake servo.

Installation note: Check gasket for non-return valve and replace if necessary.

Unclip vacuum line (1) from line clip (2).

Unlock snap fastener (3) and detach vacuum line.

Replacing vacuum hose for brake booster (diesel fuel)

Necessary preliminary tasks:

• Read and comply with GENERAL INFORMATION.
• Remove left TRAILING LINK .
• REMOVE left partition wall for units compartment.

IMPORTANT: Before beginning repair work, fully press the brake pedal several times to reduce the vacuum pressure in the brake servo.

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

Installation note: Check seal in brake booster and replace if necessary.

Disconnect snap fastener (1) and feed out vacuum line (2).

Installation note: Make sure that snap fastener (1) is correctly engaged.

Replacing vacuum hose for brake booster (petrol)

Necessary preliminary tasks:

• Read and comply with GENERAL INFORMATION.
• Remove left TRAILING LINK .
• REMOVE left partition wall for units compartment.

IMPORTANT: Before beginning repair work, fully press the brake pedal several times to reduce the vacuum pressure in the brake servo.

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

Installation note: Check seal in brake booster and replace if necessary.

Disconnect snap fastener (1) and feed out vacuum line (2).

Installation note: Make sure that snap fastener (1) is correctly engaged.