Originally Posted by Scarebird
no. their job is to limit pressure AFTER a certain point is reached. when you stamp on the brake hard they kick in, but during normal stops, they allow full pressure to the rears, allowing the rears to help stop the car.
right, and not only that. most disc/disc applications do not use them. they are used because of the self energizing ( duo servo ) drum brakes, they don't need as much brake preassure, once they rotate over ( self energize )