Roof Air Conditioner on a 5th wheel leaks when it rains

n7bsn wrote:
it's not unusual for the hold-down bolts to be loose, or the gasket age out

I agree. I recall four bolts which hold the unit down and pinch the seal to prevent leaks. I think it was a 9/16 socket that fit the bolts.

I would remove the cover on the a/c inside your rig and make sure those bolts are snug. Mine were tightened fairly tight with just a 3/8 ratchet for leverage.