Air conditioner roof bolts

calewjohnson · 02-21-2015, 11:57 PM

I pulled the center AC off this afternoon to clean the air box out (lots of wood particles made it to the center) and to do some general AC maintenance. When I put the AC back in place, I noticed the front two bolts don't snug, once bottomed out, they turn in place...the back did fine, but I don't want to trust two stripped bolts to hold the front of the AC down. If anyone has come across this, what has been your fix for this situation?

Cale

Camper2b · 02-22-2015, 02:00 AM

I can only suggest sightly bigger lag screws/bolts. Poor excuse for an installation in that department. Thats likely to happen to all of us before its over when removing and replacing unit for one reason or another.

Sinecure · 02-22-2015, 06:30 AM

Toothpicks. Put a few toothpicks in each hole and break off flush with the roof. Then tighten your lag bolts. Should be able to tighten them up then.

**wahoonc** · 02-22-2015, 11:03 AM

Quote:

Originally Posted by Sinecure

Toothpicks. Put a few toothpicks in each hole and break off flush with the roof. Then tighten your lag bolts. Should be able to tighten them up then.

The "real" fix is to clean the hole up and glue wood dowels in the hole then re-drill. I am making the assumption you have a wood frame for the A/C unit to bolt down too? If it is aluminum I would switch to threaded inserts and machine bolts. The thing doesn't have to be super tight, just enough to hold it and compress the gasket. Probably got stripped at the factory by some ham-fisted clown with an air wrench.

Aaron

calewjohnson · 02-22-2015, 01:22 PM

Quote:

Originally Posted by wahoonc

The "real" fix is to clean the hole up and glue wood dowels in the hole then re-drill. I am making the assumption you have a wood frame for the A/C unit to bolt down too? If it is aluminum I would switch to threaded inserts and machine bolts. The thing doesn't have to be super tight, just enough to hold it and compress the gasket. Probably got stripped at the factory by some ham-fisted clown with an air wrench.

Aaron

It is wood, however, I did not notice if it was in the frame or not. I will fix it next weekend for sure, but I think the forward bolts went into the plywood on the roof, which may have me looking for a metal anchor and bolt to install, otherwise I will be going the wooden dowel route. The aft bolts snugged up, but those were definitely in the framed up portion of the roof...

Cale

sundancer 87 · 02-22-2015, 02:24 PM

Do you really have a plywood roof? The kind with multiple layers of wooded bonded together or are you calling chip board or MDF plywood?

At any rate, a simple relocation of the bolt holes in the A/C bottom will get you into new material.

calewjohnson · 02-22-2015, 02:30 PM

Quote:

Originally Posted by sundancer 87

Do you really have a plywood roof? The kind with multiple layers of wooded bonded together or are you calling chip board or MDF plywood?

At any rate, a simple relocation of the bolt holes in the A/C bottom will get you into new material.

Yes, it is the chip board, the kind that looks like it went through a chipper, then was glued in layers and pressed flat...then is a complete mess when there is a crappy cut through the wood...

I could possibly move the holes, cover old with some EternaBond, but with the location of the neoprene seal (little squares sandwiched between the AC and roof at the front, not the main neoprene seal), it may be more trouble than it is worth...I will take a look though, I just hate blindly putting holes in the roof while not being able to see the wiring...

Cale

sundancer 87 · 02-22-2015, 02:38 PM

The roofing material isn't that thick, 5/16s maybe less so short bolts could be used and the chance of hitting wiring would be mitigated.

Just be mindful of that R40 insulation up there.................

sundancer 87 · 02-22-2015, 03:29 PM

Here's the solution I will use for the two slopped out bolt holes I have. I'll get two of these, the largest I can find but a 1/4 inch will do.

I'll remove the flat head machine screw from the toggle and replace it with a length of threaded rod. Insert the toggle into the roofing material and hold it in place with the Tinnermen nut, back fill the enlarged toggle hole with Dacor self leveling caulking up the the height of the weather seal gasket.

I'll use the appropriate sized hex nut and lock washer to fasten the A/C to the roof.

I'll have two lag bolts in the front and two studs in the rear holding down the A/C for future removal and maintenance of the A/C.

calewjohnson · 02-24-2015, 02:26 AM

Quote:

Originally Posted by sundancer 87

Here's the solution I will use for the two slopped out bolt holes I have. I'll get two of these, the largest I can find but a 1/4 inch will do.

I'll remove the flat head machine screw from the toggle and replace it with a length of threaded rod. Insert the toggle into the roofing material and hold it in place with the Tinnermen nut, back fill the enlarged toggle hole with Dacor self leveling caulking up the the height of the weather seal gasket.

I'll use the appropriate sized hex nut and lock washer to fasten the A/C to the roof.

I'll have two lag bolts in the front and two studs in the rear holding down the A/C for future removal and maintenance of the A/C.

So, by using the toggle with the thread rod, this will act like a guide for the AC? Then the nut and lock washer will screw on top of that. Great idea, I will have to do some looking this weekend.

Thanks again,

Cale

sundancer 87 · 02-24-2015, 12:38 PM

Quote:

Originally Posted by calewjohnson

So, by using the toggle with the thread rod, this will act like a guide for the AC? Then the nut and lock washer will screw on top of that. Great idea, I will have to do some looking this weekend.

Thanks again,

Cale

Absolutely, a solid mounting method with alignment pins.

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