Hi Tom,
Ok, that makes sense too - but how does the warning light work in conjunction with it?
-Graham.
The distribution block has a piston in it, like a wheel cylinder piston, that is centered in the bore of the block by springs. When the system is functioning properly, there is an equal amount of pressure on both sides of the piston, keeping it from moving. If one side (front or rear) of the brake system is leaking, then the pressure difference when you apply the brakes will cause the piston to compress the springs & move in the bore. When it moves far enough, it touches the contact in the block and lights up the parking brake lamp on the instrument panel. You will also notice a big drop in the brake pedal and a whole lot more pedal effort and distance is needed to stop. If you get stopped without hitting anything, you may need a lot of detergent to clean your britches. :-))
BL
