Re: Air Brake Help
Sounds like the service brake valve (the one from the brake pedal) may be sticking open. Think of the air system like a water faucet. There is water going to a faucet all the time, but unless you turn it on, no water. The air system works the same way. Air pressure is always there on one side of the system, but none on the other until you press the pedal. The only two ways to deliver air to the brakes is to open the service brake valve by steeping on the pedal, or releasing the PP1 valve (Spring Brake) to set the rear brakes. You mentioned you took the main valve off to check, and that is the most likely source of the problem. It has a diaphram inside, and if not closing properly, could be your problem. Its sounds like your looking in the right place.