34 31 181 Removing and installing / replacing expansion tank for hydraulic brake actuation

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2013 BMW 128i, 2012 BMW 128i, 2011 BMW 128i, 2010 BMW 128i, and 2009 BMW 128i. However, it is still accessible from the selected car via links, so may be relevant.

Necessary preliminary tasks:

Read and comply with General Information .
Remove lower section of microfilter housing . See 64 31 092 REMOVING AND INSTALLING/REPLACING MICROFILTER HOUSING (LOWER SECTION) .

NOTE: Extract brake fluid out of expansion tank. Use a suction bottle used exclusively for drawing off brake fluid.
Do not reuse drawn out brake fluid.

Pull off supply hose (1) of clutch hydraulic system if necessary.

Unfasten plug connection (2) and disconnect.

Unlock quick-release fastener (3) and disconnect vacuum line.

Feed brake line out of rubber grommet and remove cover (4).

Fig 1: Identifying Master Cylinder Expansion Tank, Supply Hose And Plug Connection

Courtesy of BMW OF NORTH AMERICA, INC.

Unclip locking pin (1) from retaining lugs (2) and pull out locking pin.

Pull expansion tank in direction of arrow vertically out of brake master cylinder.

Fig 2: Removing Locking Pin From Retaining Lugs

Courtesy of BMW OF NORTH AMERICA, INC.

IMPORTANT: Check rubber plug in brake master cylinder for damage and replace if necessary.
Push the expansion tank vertically onto the master brake cylinder.

Fig 3: Pushing Expansion Tank Vertically Onto Master Brake Cylinder

Courtesy of BMW OF NORTH AMERICA, INC.

After installation:

Bleed braking system