Thanks for the post Danny,

You may have a blockage in the Manifold that's causing the excessive heat and pressure, I would take the Regulator components out of the manifold as well as the check valve, see if there is debris inside the manifold that's causing this.

Otherwise, I don't see why the hose wouldn't stay on the barb fitting.

Also, does the tank hold pressure when it fills? So, when you pressurize the tank (doesn't have to be full) and shut the unit off, does the tank hold pressure as it should?

- MTR

The tube (Bleeder Tube) only has the maximum pressure of 130 PSI going through it as soon as the Unloader Valve on the switch trips, so when the unit shuts off.
The tube, if in good condition, will easily hold up to 175 PSI though.

Here's what I think could be causing it, apart from debris in the Manifold:

1. The heat from unit running so long causes the plastic tube to stretch and blow off barbed fitting. Use a small hose clamp (instead of a wire tie) to keep tube attached to barbed fitting.

2. Unit needs the valve plate gaskets replaced if not blowing air out the pump breather vent. Do you feel air escaping from the pump Breather vent (as you should)? The breather vent should be located on the side of the cylinder, on the exhaust side of the pump.
- If air is blowing out breather, you may need the rings replaced in the pump.

- MTR

In that case, it could very well be that the Gaskets need to be replaced, which we have available on our site at the below link:

www.mastertoolrepair.com/portable-oil-ba...602713-p-748807.html

You've narrowed it down to the gaskets, not sure what else it could be. I would replace the Gaskets then see what you get.
For more assistance, you can contact Coleman-Sanborn if you would like, their phone# is 888-895-4549.

- MTR