Coleman Mach 3 screws coming loose

Yeah. Most RV owners don't know you should re-torque them periodically. That is usually the first place a roof gets damaged for just that reason.

Some OEM's (OLD Winnebago's) they used a spring for each mount bolt to keep the tension on the bolts. The bolts come loose from the AC Gasket compressing over time. Are you using OEM(Coleman) gasket or a after market gasket? Doug

You mention installing a new gasket. I agree with, in time, most new trailers, or trailers with new gasket, will experience bolts a bit loose. After snugging them a bit, a time or two, this should not continue.

Jerry

It's not just that the bolts will loosen from the gasket sagging with age, they will keep working their way out (presumably from going over bumps while towing) so the mounting bracket and control panel are hanging down by an inch or more from the ceiling after a few trips. The original gasket didn't hold up very well and started leaking when it rained. The aftermarket one seems to be holding up better, and the upper unit is still sitting at the right height and sealing all around. Even if I snug them up, the whole thing will soon be hanging way down from the ceiling. I understand they might need to be snugged up periodically, but it seems they had very little resistance and would vibrate themselves on out.

That much loosening, I would not call normal. Loctite should help. Unless the AC itself vibrates during use, causing bolts to loosen, I'd wonder about the whole trailer vibrating, from driving too fast on very rough roads, or possibly a suspension issue, maybe tire/wheel way out of balance.

Ask the wife to ride in trailer for a while, see how it rides, any vibration etc. Just don't forget she is back there, if on a day long trip! :)

Jerry