Quick Release Valves

Quick release valves were developed to speed up the release of air from the brake chambers to let the brakes release quicker. There is typically a single supply port and two delivery ports. As the brake pedal is depressed and air flows toward the brake chamber, it passes through the quick release valve which is mounted nearby the chamber. The air pressure is held until the pedal is released. When the supply pressure at the quick release valve drops, the air in the brake chamber is released out the bottom of the quick release valve rather than having to travel all the way back to the relay valve's exhaust port.