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Air Brake Relay Valve Exhaust Leak


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Hey guys, im having an issue with my air brake relay valve on my 2005 Mack CHN613 that I can't seem to figure out.

When I release the air brakes (push in yellow valve) I get a constant exhaust leak out of my relay valve. When I apply the foot brakes the exhaust leaks stops, and when I pull the yellow valve the leak stops as well. I cant figure out what might be causing this constant exhaust leak.

I have an R-14H relay vave from Bendix. I replaced all the interals (O-Rings, Piston, Spring) and I am still having this issue. 

Any advice would be appreciated.


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Another thing to mention is, when I have the yellow valve pushed in, I have a constant supply of air coming into the R14 from the quick release valve balance port. I disconnected the supply port from the QR valve and that is supplying the air. Im not sure if this is normal operation, or if there is a diapharm between supply and balance that is torn, but this is whats causing the leak i think.

Edited by ivanuke
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Thank you for the reply. I think I may have found the problem. I disassembled the quick release valve supply inlet and found the rubber diaphram had a hole in it. I cut a piece of rubber the same size and put it in its place. It seems to be working fine now. The auto parts store is closed today so I will have to buy a replacement valve in the morning.

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