Isn't that a pressure protection valve? It looks like this:
http://www.everythingtruckparts.com/bend...7AodnwYAHw
There should be several of those around the coach. Essentially check valves to hold pressure into a given system, while letting 2 way flow occur if the pressure is high enough on both sides of the valve (typically 65 psi). If the pressure drops low enough on either side, the vavle shuts and prevents further loss.
Exactly!
That's the culprit. The Newell service Dept. gave it the DOT valve name. Probably a safety requirement by that Dept. That ppv controls all of the supply side. It is the only one I see under the Coach. Could the others look something like this one?
i had to replace a couple of proportioning valves on the rear brakes. are they the same?
i dont think so
tom
Tom they call it the DOT valve because its required by the DOT as a last chance in the event of air failure.
If you were driving a big rig truck with a trailer. The trailer would also have one. The proportional valves serve a different purpose.
yea, i just looked it up. i see what it does now.
thanks jimmy
tom
There could be a ppv at each air tank and one in the accessory air system (pocket doors, etc and air compressor). Any system that's tied to the main air system will have a ppv between it and the main system. They should really be considered a maintenance item and I do need to replace mine.
I've been told that if they're in a tight location and if you can source the original, you can take the four screws out of the tophat, swap out the guts after ensuring its clean and put the tophat back on. Supposedly there's no reason to remove the main body.