34 00 017 Checking brake booster (low-pressure test)

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2010 BMW 535xi, 2010 BMW 535i, 2009 BMW 535xi, 2009 BMW 535i, and 2008 BMW 535xi. However, it is still accessible from the selected car via links, so may be relevant.

Special tools required:

34 3 100

Necessary preliminary tasks:

REMOVE LEFT MICROFILTER HOUSING

Detach hose from connection piece. Install vacuum tester 34 3 100 between connection piece and vacuum hose of non-return valve.
Start engine.
Check buildup of partial vacuum.
Switch off engine.
Press the brake pedal to set a vacuum pressure of not more than 0.8 bar and wait for the value to stabilize.
When the brake pedal is not pressed, the vacuum pressure is permitted to drop over a test period of 1 minute by max. 0.06 bar.

Fig 1: Identifying Vacuum Tester 34 3 100 Between Connection Piece And Vacuum Hose Of Non-Return Valve
Courtesy of BMW OF NORTH AMERICA, INC.

If specified values are not reached:

Check line connections for vacuum seal.
Replace non-return valve.
Check seal between brake booster and brake master cylinder (sealing ring) for perfect condition and correct seating.
If the specified values are not achieved when the test is repeated, you must replace the brake booster.