See also:

Removing a wheel
Unscrew the uppermost wheel bolt completely. Screw alignment bolt 1 into the thread instead of the wheel bolt. Unscrew the remaining wheel bolts fully. Do not place wheel bolts in sand ...

Brake fluid level
If you notice that the brake fluid level in the brake fluid reservoir has fallen to the MIN mark or less, check the brake system immediately for leaks. Also check the thickness of the brake ...

BAS PLUS (Brake Assist System Plus)
BAS PLUS is only available in vehicles equipped with DISTRONIC PLUS. Observe the "Important safety notes" section. At speeds above approximately 20 mph (30 km/h), BAS PLUS assists ...