[Richard]

Terry, I went out and took a hard look at mine, and you are correct on the in and out of the air doubler.

Let’s do some incredibly basic checks. I don’t know what you have tried, so forgive me if I am suggesting things that are already established. I am not intentionally trying to insult anyone, but rather eliminating the basics before complete disassembly of the coach ;_0

First, without the air line plugged into the chuck, when you open the 1/4 turn on the air line from the compressor do you get air?

Second, with the engine running to make BIG air, if you plug into that port, do you get air?

Third, and I am really fuzzy on this one. If I interpret your comments correctly, you have such a massive leak that the on board compressor cycles every couple of minutes. When the on board cycles, how much pressure builds?

Massive leaks like that are usually one of two things, a blown slide seal or an air line that has cracked,ruptured, or slipped out of its fitting.

To get you in business quickly, you could alter the air line plumbing with tee at the on board compressor to accept the input from your skid compressor. BTW, those HF compressors are pretty dang quiet.