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Discussion Starter · #1 ·
My 25 year old chain drive unit died. A gear inside completely sheared in half so without an unavailable 25 year old replacement part, it's a write-off.

I was hoping to re-use the existing mounting brackets, and even the existing rail if possible. The existing rail is a single metal "T" shape, rather than the multi-piece hollow bars that come with the new kit. Being one piece, it's nice and solid.

I bought a new unit and discovered some things I didn't know. I can still return it though.
I had thought "hey, let's try a belt drive unit because they're quieter and it's directly under my living room"
So the first thing I learned is that a belt drive will absolutely require replacing the existing rail with the one from the kit. Ok, I could live with that, but...
The second thing I learned is that the rail from the kit is about 8 inches shorter than the existing rail. That would require me to move the mounting brackets in a way that would be surprisingly complex. Right now, the existing unit mounts directly below a joist. 8 inches will put it halfway between joists, so I'll have to make brackets that bridge between two joists and not block the power outlet that is right there! Of course this is doable, but it's just annoying.

So I'm thinking of returning the belt unit and buying a chain unit.

Ok, questions start here.
1. Is it possible my chain is a non-standard length? The distance from sprocket to sprocket is about 120 inches. The door is 7 feet 1 inch tall.
2. Are chains standard in terms of chain link size? In other words, could I reuse the existing chain on a new chain unit? I'd rather use a new chain, but if it's shorter then I can't reuse the existing mounting brackets or rail.
3. I see chain extension kits that come with replacement rails. If the new chain is too short, is there a way to extend it to exactly the length of the old chain and not bother getting yet another rail I don't want to use?
4. The instructions with the new kit say "doors taller than 7' up to 8' tall require a rail extension kit". What do they mean? Do they mean the regular kit will work with doors between 7' and 8', or do they mean you need the extension for over 7', and the extension allows up to 8'? That's terribly poorly worded. I will phone the manufacturer to ask, but figured someone might have experience with this.
5. Is there something else you think I should do? Keep the belt unit, buy more angle brackets to bridge between joists and forget reusing anything?

I can post pictures, but I don't think they're needed at this point.

Thanks!
 

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Naildriver
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Agree. Don't understand why you would want to mix old worn parts with new ones. Too easy to change the whole thing out and watch the game on TV. You are not guaranteed any parts from one opener will even come close to fitting another.
 

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Discussion Starter · #4 ·
Thanks, Chandler, XSleeper,

Mounting a new motor unit on the existing mounting brackets and rail would take 10 minutes, while constructing a new set of mounting brackets positioning the unit halfway between joists (because the new rail is 8 inches shorter) is going to take a lot longer.

The ceiling is finished, the unit sits almost a foot below it, and the power outlet is between those joists such that if I ran angle brackets on the ceiling between the joists, one would run into the outlet! So I have to run the angle brackets first along the two joists, drop four verticals (ok, two already exist), then bridge horizontally between those verticals. It's just a lot more stuff to line up just right, compared to the existing position with only one against the ceiling (along the joist) plus two verticals, no other horizontals because the unit is directly below the joist.

I also just like the solidity of the existing one-piece rail, but maybe that's just a silly prejudice.
(Is it just a silly prejudice?)

I guess now is the right time to include a photo.
654848

Is there a simpler way than what I've described to hang the new unit halfway between the joist that has the current bracket and the next closer joist (which is where you think it is, beside the power outlet, closer to us)?

One positive development - I called the company about the "7' up to 8' " instructions and a 7'1" door counts as a seven foot door. It would really have upset me to build new mounting and then discover I need a rail extension kit for one more inch of door!

Thanks!
 

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Discussion Starter · #5 ·
If you're wondering why I took the old unit apart in mid air like that, I was trying to find out what was wrong with it.
654853

"Well, there's your problem!"
 

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Usually Confused
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I'm a bit surprised that you couldn't get a replacement gear set- most common brands do. I don't know what the exact specs are but mine(~25 years old) has an extension kit and, obviously a longer chain. I would re-use the old chain - it's probably stretched.
 

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Discussion Starter · #7 ·
I'm a bit surprised that you couldn't get a replacement gear set- most common brands do.
It's a "Moore o matic" X125.
Moore was bought by Linear at some point.
The broken part ought to be part A6721 on the last page of this pdf, but that has 38 teeth, while mine has 20 (and no gear in that parts list has 20 teeth!)
I've searched for that part number and got nowhere.

Doing a more generic search, this looks very close to the full assembly, but it has 8 teeth on the chain sprocket where I have 10, and it looks like about 32 teeth on the main gear where I have 20.

This looks a lot like the broken main gear, but again it has 32 teeth, not 20

Another 32 tooth gear

I just can't find this. If it was a Liftmaster, it would be all good.
 

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Is there a simpler way than what I've described
You need to install 2 angle brackets on the ceiling perpendicular to the joists. (Each end will catch a different joist) These brackets would be about 24" long. The flat sides of these brackets will be spaced as wide as your new unit is, and 4 lag screws attach them.

Then you drop down 2 angle brackets that are long enough to hang the new opener at the correct height, and attach the opener with 2 bolts. Then you put one angle bracket diagonally above the opener on those last 2 brackets. You don't need diagonal angle brackets the other direction because the rail is screwed to the wall and isn't going to sway front to back.

The time it takes to put up these 5 pieces is just part of the job. You typically lay the rail on top of the fully open garage door while its resting on a 2x4 spracer and that's the optimum height. Unless the instructions say different.
 

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Yup, the same as the ones on ebay. Looks like it will fit. Think I'll give it a shot.
I just have to figure out how these retaining pins come out.
You might not have to. A lot of the gears just nestle in the pin.
 

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Discussion Starter · #13 ·
You need to install 2 angle brackets on the ceiling perpendicular to the joists. (Each end will catch a different joist) These brackets would be about 24" long. The flat sides of these brackets will be spaced as wide as your new unit is ... .
However, as I said, and showed in the photo, I don't get to do that because of where the electrical outlet is. :(
 

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A new unit may be a different width than your current one... If its really in the way, move the outlet, repair the drywall. Or put a 2x2 (or narrow rip of 1/2" plywood) on each joist to shim your first two brackets down so they pass right over the outlet cover. You can still surely plug into one side or the other.

Even some large washers under your brackets would work to shim them down so that they pass over the outlet cover.
 

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Discussion Starter · #15 ·
Or put a 2x2 (or narrow rip of 1/2" plywood) on each joist to shim your first two brackets down so they pass right over the outlet cover. You can still surely plug into one side or the other.
Ok, that's a good solution. I have multiple choices for the wood from my scrap collection. Thanks!
 
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