# Craftsman garage door opener repair (broken trolley?)



## iamrfixit (Jan 30, 2011)

That is the old style T-rail trolley, there are plenty of them around as they were made by chamberlain for Sears, Liftmaster, Master mechanic, do it best and probably a few others from the early 80's on. If you use Ebay there are tons of them on there, Link to Ebay or here is a link to one on Amazon.com. A new one may be slightly different as the later model openers no longer used the spring, but it works fine without the spring, you simply install a nut on either side of the adjuster and tighten the adjusting screw down solid.


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## Simon96Taco (Nov 11, 2009)

Thanks so much! The ones you linked don't seem to want to ship to Canada, but I found the exact same part on the .ca Amazon page.

Thanks again! I'll let you know how the install goes


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## Simon96Taco (Nov 11, 2009)

iamrfixit said:


> That is the old style T-rail trolley, there are plenty of them around as they were made by chamberlain for Sears, Liftmaster, Master mechanic, do it best and probably a few others from the early 80's on. If you use Ebay there are tons of them on there, Link to Ebay or here is a link to one on Amazon.com. A new one may be slightly different as the later model openers no longer used the spring, but it works fine without the spring, you simply install a nut on either side of the adjuster and tighten the adjusting screw down solid.


So, the part finally arrived from Amazon. I'm still trying to get the old trolley off, but once I do, do I completely throw away that long threaded rod (with the spring on it) when I put the new trolley on?


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## iamrfixit (Jan 30, 2011)

You will need to take the rail loose from the motor, or separate the rail sections to be able to get the old trolley off and the new one on. Make sure you install it on the rail in the correct orientation, the emergency release should point toward the motor.

Not sure what your new trolley came with, you still need the threaded adjustment rod to tension the chain. Older openers had the springs, on newer chain drive openers they eliminated the springs. 

The cable (or in some cases the chain) attaches to the front of the trolley with a master link, and the chain attaches to the threaded adjuster also with a chain master link. If you have all the pieces and they are in good shape you can reuse the spring assembly. Otherwise the adjuster can be used with a nut on one side and a nut and lock washer on the other side to secure it to the trolley. At approx 30 seconds in this video you can get a good view of the tension adjuster without the springs. 

The chain should be tightened until it sags only slightly, about 1/2 - 3/4" over the length of the rail. Too much tension can wear parts quickly, if it's too loose and the chain may not stay on the sprockets. 

In your pic the spring and tensioner is either assembled incorrectly or missing pieces, I can't tell as the picture is zoomed too far.


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## Simon96Taco (Nov 11, 2009)

Got it!

I detached the rail from the front (door) end and lowered it a few inches, that allowed me to slide the old, broken trolley off. Slid the new trolley back on.

I used the chain extension (which came with the new trolley) to extend the cable so it would reach the new trolley (my opener has chain on one side and wire/cable on the other). After a bit of trial and error in putting it back together, including forgettinng one of the bolts attaching the door arm to the trolley....it's working again!

Thanks again, iamrfixit.


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