BAS Brake Booster

Location
In the left of the components compartment.

Task
Like a conventional brake booster, the Brake Assist (BAS) brake booster boosts the force applied by the driver's foot when braking and performs BAS braking.






Design
Vacuum brake booster with one or two diaphragms. The BAS solenoid valve (y1) and BAS release switch (s1) are permanently installed in the BAS brake booster (not replaceable). The BAS diaphragm travel sensor (b1) and, where applicable, the BAS control module (N48) are attached to the brake booster (replaceable).

Function
Basic function like conventional brake booster.
Emergency braking is established by the BAS control module by means of the BAS diaphragm travel sensor (b1). With BAS braking the BAS solenoid valve (y1) opens the valve (d) which introduces atmospheric pressure from the air cleaners (g and f) to the backs of the rolling diaphragms. The full boost pressure of the brake booster is transmitted to the master brake cylinder by the thrust piece (h).
When braking is finished the control module receives a signal from the BAS release switch (s1) and BAS solenoid valve (y1) is closed again. The BAS boost is terminated.