I bought a 1997 Doonan 53' drop deck and it has an air pressure regulator inline on the back axle. I need to adjust it everytime I have a load or am empty because the back axle will either be way over inflated when empty or the front axle will carry most all the load when loaded. It's a POS as is. I called Doonan and they said that's the way they came out back then. It makes the trailer a piece of crap and I want to change it to the way they are plumbed now but the guy didn't know for sure and said to take it to a trailer repair shop. Do anyone know or have diagrams and pictures what I might need to do to get rid of it and make it work like it should?

tia

 

Just take the valve out and eliminate it, no harm done, all 4 bags should be in series UNLESS you have a dump axle or lift axle