BAC Forum

General Boards => Technical Support => Topic started by: Gary Nash on February 10, 2015, 12:05:54 AM

Title: Roof AC Mounting Bolts
Post by: Gary Nash on February 10, 2015, 12:05:54 AM
I have a leak around my Duo-Therm AC. Was going to tighten the mounting bolts. The insructions call for 40 to 50# on the mounting bolts. The bolts look like 1/4" bolts. Will the bolts take 40#'s?
Gary
Title: Re: Roof AC Mounting Bolts
Post by: Gary Nash on February 10, 2015, 12:18:36 AM
I found the answer to my question.  My 40-50 is in inch lbs. I was thinking of ft. Lbs.
Title: Re: Roof AC Mounting Bolts
Post by: Gary Wolfer on February 10, 2015, 04:28:21 AM
Took the words right out of my mouth. they loosen up occasionally. If the leak is coming down the bolts holding the unit on I have a fix for it if it does not quit when you tighten it up. Good Luck
Title: Re: Roof AC Mounting Bolts
Post by: Joel Ashley on February 10, 2015, 08:14:11 AM
Be sure not to overtighten them or you'll deform the gasket on the roof, and that can make things worse.  Then you'll have to go up and replace the gasket.

I just check mine occasionally, that the bolts/nuts aren't noticeably loose, and that they are snugged up.

Joel
Title: Re: Roof AC Mounting Bolts
Post by: William Jordan on February 10, 2015, 07:37:47 PM
From my prior RV experience, do not tighten too much, 40- 50 ftlb seems like too much. The are just suppose to be very " snug " I installed a new replacement unit on my 5th wheel and it was very easy but the instructions were very clear to not flatten the gasket out or you'd have to replace it.!  It's very easy and cheap to replace the gasket by the way. 4 bolts and electric harness unhooked lift the unit ( the hard part) clean and place gasket reconnect,done. That may be your easiest answer to leaks
Title: Re: Roof AC Mounting Bolts
Post by: Keith Moffett on February 11, 2015, 01:24:03 AM
Roofs are built differently on trailers, entry level MH's and ones like ours.  Beavers I believe have polystyrene in the roof instead of styrofoam.  While this is a good thing, it cuts both ways.  Styrofoam has a certain felx that polystyrene does not which means it wont bounce back once it is compressed.  This can result in a dished roof around the AC units if they are over tightened.
Also there was a foam gasket under many AC's in entry level units.  This would deform with age and lose its seal.  Newer gaskets are urathane and have more spring to them so dont lose the seal very often and require less retightening.
BTW!  I have not tried it but have heard of a fix for roofs that are dished around the AC.
Title: Re: Roof AC Mounting Bolts
Post by: Gerald Farris on February 11, 2015, 02:32:57 PM
The correction for a coach with a dished roof around the air condition that Keith is probably referring to in the previous post is to remove the air conditioner and insert thin plywood into the space directly below the fiberglass by using the A/C cutout opening as the entry point. You keep the plywood very even under the gasket matting surface, and use the minimum thickness to correct the dip. This correction does work, but it is a lot of work, can be expensive, and should only be used when necessary.

Gerald