Overview of brake master cylinder/brake booster

Courtesy of BMW OF NORTH AMERICA, INC.

1. EXPANSION TANK .
2. BRAKE MASTER CYLINDER .
3. NON-RETURN VALVE .
4. BRAKE SERVO .
5. VACUUM HOSE .
6. Bleed breaking System. Refer to BLEEDING BRAKE SYSTEM WITH DSC  or REPLACING FLUID IN BRAKE SYSTEM .