Brake Lines, Brake Hoses: Brake Lining Wear Indicator

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.

Brake lines and brake hoses must be correctly routed and must not abut with body or components in a way which would cause chafing.
To prevent damage, release and tighten brake line couplings with a special brake line wrench only.
The system must be bled each time any brake lines have been detached.
All connection points must be checked for leaks.
Only tighten down brake hoses on the front axle when wheels are in straight-ahead position.
Close open connections on brake lines and individual components to prevent dirt from entering the brake system.
Observe tightening torques when tightening down brake line screw connections.
Tightening torque, refer to 34 32 1AZ in BRAKES - TIGHTENING TORQUES - E60 .