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

WARNING: This page is about a different car, the 2007 BMW 550i, 2006 BMW 550i, 2005 BMW 545i, and 2004 BMW 545i. However, it is still accessible from the selected car via links, so may be relevant.

NOTE:

For Special Tool identification, see BRAKES - SPECIAL TOOLS - 5-SERIES (E60) .

Special Tools Required:

34 3 100

Necessary Preliminary Tasks:

Remove left microfilter housing. Refer to 64 31 061 REMOVING AND INSTALLING/REPLACING LEFT OR RIGHT MICROFILTER HOUSING LOWER SECTION .

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: View Of Brake Booster Tester
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.