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

WARNING: This page does not describe the selected car, but rather 15 other vehicles, including the 2008 BMW 335xi, 2008 BMW 335i, 2008 BMW 328xi, 2008 BMW 328i, and 2008 BMW 323i. 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

NOTE: Suck the brake fluid out of the expansion tank. Use a suction bottle used exclusively for drawing off brake fluid.

Do not reuse drawn out brake fluid.

After completing work:

Bleeding Braking System

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 Expansion Tank Cover, Supply Hose, Plug Connection And Quick-Release Fastener

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: Identifying Expansion Tank Locking Pin And 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.