Normal Mode

Braking In Normal Mode
The The Brake Assist (BAS) brake booster (A7/7) is continuously supplied via the vacuum pipe with intake pipe vacuum or pump vacuum an the diesel. When the brake pedal is not operated the same vacuum prevails on both sides of the diaphragms. The compression spring holds the diaphragm plate in its initial position.

When braking outside air is lead to the back of the diaphragms via a port. As braking takes place increasing pressure difference occurs between the front and back chamber of the booster which acts in the direction of the master brake cylinder and thus boosts the force applied by the driver's foot.