All modern vehicles use some type of power assist for the braking system. The 8 cylinder models being recalled use a vacuum pump, connected to the power booster by a vacuum hose, to provide the necessary assist. The vacuum pump may leak a small amount of lubricating oil into the vacuum hose and this contamination could result in a loss of power assist, leading to increased stopping distances. Dealers will correct this concern by replacing the brake vacuum line with an improved version.
Car Recalls
Recalls are issued for cars with safety-related defects or problems
2010 BMW X5 M recalls
The Brake System Power Assist May Fail
Brakes, February 7, 2013