Flushing Brake System Completely
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 2010 BMW M6, 2010 BMW 650i, 2009 BMW M6, 2009 BMW 650i, and 2008 BMW M6. However, it is still accessible from the selected car via links, so may be relevant.
Connect bleeder hose with collecting tray to bleeder valve on rear right brake caliper.
Open bleeder valve and purge until clear, bubble-free brake fluid emerges.
Close bleed valve.
Follow same procedure on rear left, front right and front left wheel brake.