[Richard]

The shop air did NOT blow your slide seal. Not saying you don’t have a blown seal, you will not hear it with the engine running, but putting air into the air chuck with an external compressor is NO different than putting air into the system with the engine compressor.

There are all kinds of info in your previous comments on this thread and your ride height thread.

The 120V compressor does not work.
I have a massive leak down.
I only hear air when hooked to shop air.

Let’s take these one at a time..

I only hear air when hooked to shop air. Well, you cannot hear an air leak with the engine running, especially since you have hinted the muffler is kaput. Use the shop air to find your leak, turn down the regulator on the shop air to 30 or so, to help locate the leak without causing a hurricane.

I have a massive leak down. Can you quantify this. Build to 120, turn off the engine, and how many minutes to lose 40 psi on the gauge?

The 120V pump doesn’t work. First is is getting power? A voltmeter will tell you that. Is it getting power but not turning? Bad capacitor or burned up motor. Is it turning? Disconnect the air line at the pump and install a gauge to see if the pump willl make pressure. Given the coach is new to you, and with the air leak issues, the 120V air compressor took a beating.

One thing you want to do while under a cribbed coach is bleed the round wet tank in the rear, the two round brake tanks in the front, and the ping tank in the passenger drive tire well. You likely have water in those tanks from the compressor running incessantly due to the leaks.