AC Mounting Bolt Question

[goobscoob]

New AC did not come with mounting bolts or installation instructions.
Old Mounting Bolts too large diameter
Sales rep: "blahblahblah"
Googled install instructions, calls for 1/4 bolts
Bought some 1/4 bolts. They thread in just fine all the way but they are a tad jiggly. Not so jiggly that they come out, I can pull with all my hand force and nothing even while jiggling them, they won't move but I'm worried when I torque them down to instruction specs (50lbs or gaskets compressed 1/2) that they might strip the nuts in the AC. Is it normal to have a little play in these or should I ignore instructions and try to go up .5m or 1m?

It also seems a lil bizarre to me that all the torque holding on this AC is on the 14x14 square and there's nothing to stop the rear of the AC from moving laterally in the event of a good bump or should I decide to join demo derby trailer style and need to make some sharp turns...

[Jammer]

Sounds like you have the wrong bolts

If the 14x14 is properly reinforced, a gasket is used, and the bolts are torqued, the ac should be well and truly secured in place

[tjdonahoe]

Maybe 5/16 or a metric size?

[J. Morgan]

50 pounds of torque is not right.

That is WAY too tight for a 1/4" bolt, and way too tight for the job it will be doing.

Torque it to 50 foot pounds and something WILL BREAK.

50 inch pounds is going to be closer than 50 foot pounds.


Superat stultitia.

https://www.boltdepot.com/fastener-i...ed-Torque.aspx

[TG Twinkie]

Are you sure it's not 50 inch pounds?
Sounds like you don't have the right bolts.
I would think you could find a PDF with install instructions on the net.

[joel]

Most of the instructions used to say tighten until the gasket compresses down. I have installed about 10 AC units and usually compress the gasket down about 1\3 it's thickness some gaskets have a tab on the inside that you tighten till it touches the trailer. Do not go to 50 ft lbs.the gaskets are made of a material that resists slipping .good luck.

[NOAZRK2690]

With your interior air distribution cover off, look to see if the gasket and air conditioner is sitting directly over an aluminum roof rafter on the front and rear of the unit. Airstream cut my A/C hole just a little forward of the rafter so when the tie down bolts were tightened, they just pushed the aluminum skin down. I remedied the problem by cutting a piece of wood to exactly fit aside the aluminum rafter then screwed the two together. This little extension allowed the A/C tie down bolts to actually pull against something solid. No leaks and no loose screws. Also, if you have room and your screws seem to be hitting the bottom of the nut threads, try putting a pile of washers on the head before installing the tie down screws or get the next size shorter bolt.

[Burnside Bob]

Originally Posted by goobscoob

New AC did not come with mounting bolts or installation instructions.
Old Mounting Bolts too large diameter
Sales rep: "blahblahblah"
Googled install instructions, calls for 1/4 bolts
Bought some 1/4 bolts. They thread in just fine all the way but they are a tad jiggly. Not so jiggly that they come out, I can pull with all my hand force and nothing even while jiggling them, they won't move but I'm worried when I torque them down to instruction specs (50lbs or gaskets compressed 1/2) that they might strip the nuts in the AC. Is it normal to have a little play in these or should I ignore instructions and try to go up .5m or 1m?

It also seems a lil bizarre to me that all the torque holding on this AC is on the 14x14 square and there's nothing to stop the rear of the AC from moving laterally in the event of a good bump or should I decide to join demo derby trailer style and need to make some sharp turns...

I recently installed a Dometic Penguin II AC. I found the bolts inside the styrofoam blocks that kept the Penguin II from moving in the shipping carton. But I didn't find any instructions!! So you might check the shipping carton for the bolts if you still have it.

My old AC was also a Dometic and used the same bolt, so I have two extra bolts--PM me and I'll mail them to you. The Dometic bolts have a self locking wide head and a better anti-rust coating than what you can buy at the hardware store.

From Lewster's excellent thread on installing a Dometic AC with the drain cup kit, I did know to tighten the bolts until the 14 x 14 gasket was compressed to 1/2 original thickness. The bolts got tight before I compressed the gasket that much so I stopped. Would guess I compressed the gasket about 1/4 of its total thickness before it seemed like I was applying too much torque.

It bothered me that I didn't reach 'spec' on the gasket compression, so I pulled the interior AC shroud yesterday after returning from a short trip and was surprised to find all 4 bolts loose (gasket remains compressed). I resnugged the bolts and the gasket is now compressed to about 1/2 its original thickness.

Now I'm worried that the gasket will gradually flatten and relax until it doesn't hold tension on the bolts. So I'm planning on rechecking bolt tension in another couple months.

Yep, kinda creepy that that AC is just sitting up there with no direct restraint.

[goobscoob]

Originally Posted by Burnside Bob

I recently installed a Dometic Penguin II AC. I found the bolts inside the styrofoam blocks that kept the Penguin II from moving in the shipping carton. But I didn't find any instructions!! So you might check the shipping carton for the bolts if you still have it.

My old AC was also a Dometic and used the same bolt, so I have two extra bolts--PM me and I'll mail them to you. The Dometic bolts have a self locking wide head and a better anti-rust coating than what you can buy at the hardware store.

From Lewster's excellent thread on installing a Dometic AC with the drain cup kit, I did know to tighten the bolts until the 14 x 14 gasket was compressed to 1/2 original thickness. The bolts got tight before I compressed the gasket that much so I stopped. Would guess I compressed the gasket about 1/4 of its total thickness before it seemed like I was applying too much torque.

It bothered me that I didn't reach 'spec' on the gasket compression, so I pulled the interior AC shroud yesterday after returning from a short trip and was surprised to find all 4 bolts loose (gasket remains compressed). I resnugged the bolts and the gasket is now compressed to about 1/2 its original thickness.

Now I'm worried that the gasket will gradually flatten and relax until it doesn't hold tension on the bolts. So I'm planning on rechecking bolt tension in another couple months.

Yep, kinda creepy that that AC is just sitting up there with no direct restraint.

Ours is a Dometic Penguin 2 as well, and did not come with bolts nor instructions. I had already torn the packing apart just to be certain they weren't hidden away somewhere, and I searched the foam blocks and cardboard blocks as well after your post but no luck. I think the lack of coating may be what adds ever so minutely to the diameter of the bolts because I found some 1/4 galvanized that fit more snugly. Unfortunately they weren't fully threaded so I couldn't use them. I searched 4 different hardware stores in town and could find no bolts that fit the bill except 3x at lowes why not just 1 more!I was able to google pdf instructions and I also found Lewsters' tips on installing the drain kit. I just pulled that 50lbs torque number out of my head when I made that last post, didn't mean it literally, I'll go by the gasket compression thickness. It is good to know of your experience though so I'll be sure and re-check the snugness of them frequently, especially early after install.

I appreciate your offer of mailing me the bolts and I may take you up on it if I am defeated by the hunt, though for the time being I'm going to keep searching here in town and see if I can't find 4x of the same type, simply for uniformity's sake and to save you the hassle of shipping them.

As for the way the rear end is not held down... Haha well it's good to know I'm not the only one that thinks it's a little risky but I guess if nobody else has had issues then maybe I shouldn't bother about it. I don't want to drill more holes in the roof that weren't there before unless it's absolutely 100% necessary. Good luck to us!

Thanks all for your suggestions, I probably should have been a little more clear as to the status of the project and what information I was seeking. I will do better next time.
Regards,
M

[HiJoeSilver]

Instead of locktite on the threads you can wrap a little Teflon tape (plumbing type)spiraled down the length of the bolt (candy cane style)it helps take out the play and keep them snug.

[goobscoob]

Well I ended up sending the lower shroud they sent me back as it was the wrong one. The new one arrived and it had bolts in the packing foam but only 3 of them! Dawgonnit. But yeah they are a lot better than the bolts I was originally going to use