On my way to Florida in October, I almost made it. About 50 miles from my RV park, along I75 near Sarasota, I began losing air pressure and my air brakes started dragging.

I pulled over and discovered my air dryer was venting pressure. When the air compressor hits full pressure (about 120 psi) the compressor kicks off and the air dryer is supposed to vent briefly to dump air from the dryer. Unfortunately it was stuck open and venting constantly. I was unable to get the dump valve to reseat and hold pressure.

I had a small compressor with me. I fired up the generator, plugged in the compressor and attached it to the air service fitting in the front of the coach. Even with my additional compressor I had barely enough pressure to keep the brakes off. I limped to the next exit and pulled into a nearby ball field parking lot.

I called a service guy, who showed up promptly. We decided we could just bypass the air dryer temporarily to get me to the park. He had the necessary fittings to connect input and output lines together and I drove the rest of the way to my site.

The air dryer is both a dryer and a filter so it is needed to prevent contamination of the entire air system. It is mounted on the outside of the right frame, near the engine. I removed the air dryer. It was dirty, corroded, and 25 years old. One input hose, one output hose, one small control hose, an electrical heater plug and a couple mounting bolts. New ones are no longer produced but there are rebuilt units available.

It pays to shop around. Rebuilt units went from about $400 up to almost $600. Some suppliers had them in stock, others were backordered. Some required a $120 core deposit, others not. I found one on Ebay for $419, free shipping, no core charge.

I had to remove and reuse the original input and output hose fittings and a small bypass line between them. Also I had to splice my old connector onto the new unit wires.

New and old units:

New one ready to go:

Using an exact replacement saved me having to change mounting brackets. It mounts vertically with a bolt at the bottom and a clamp ring around the middle.

Installed and ready to go. Looking forward alongside the frame. Stainless input line from compressor, output to the chassis.

I will pressure test next time I start.

Pressure tested ok. Good to go.

Knowing that it was ok and easy to bypass the dryer would have saved me time and money on the side of the road. As it was, I only lost a couple of hours and I was in a safe place.

When I get home, I plan to replace the stainless hose from compressor to dryer. It is kinked and it appears to be OEM. I will probably replace the governor on the compressor as well. Most of the other air system components have been serviced or replaced. That should take care of my air system for a while.

Have Barth, will travel again