# Craftsman garage door opener repair: Part II



## Simon96Taco (Nov 11, 2009)

Well, after posting my questions and getting the fix from this forum several months back, my garage door has had another.....setback.

This time, it looks like the sprocket (on the top of the opener unit) that turns the chain that pulls the door up - has broken off of the unit. It looks like the metal has sheared off.

I don't have a clue if the sprocket can be replaced, and wondered if anyone here would know that. My first thoughts were that I would have to replace the whole unit, track, etc., and really hope that isn't the case. 

Attaching a few pics for clarity - first, the broken sprocket in hand:










Next, a view into the space on top of the unit, where the sprocket (I assume) used to stick out of the unit for the chain to grab onto:










And lastly, one more of the overall unit/mounting:










If anyone here knows about the insides of these things and can advise or help, it would be greatly appreciated. As usual, many thanks in advance!

S


----------



## kb3ca (Aug 22, 2008)

Try going on-line to Sears website to see if parts are available. Probably can also see a diagram of the unit and parts list.


----------



## chitownken (Nov 22, 2012)

Should be able to replace the shaft that has that sprocket. As long as the GDO is not so old that the part is no longer available.


----------



## iamrfixit (Jan 30, 2011)

I have seen that a few times, the chain may have been too tight, have also seen the washer wear into the shaft and spin in such a way that it actually cuts the shaft right off. 

You can buy the gear kit complete with this shaft assembly. The shaft, complete with sprocket and bushing is held in with 3 screws and fits into another bushing below the main gear. Here is a link to the parts. You will have to take the opener down since it is mounted against the ceiling. It's a fairly easy fix. I don't usually change the worm gear on the motor unless I have to. The worm gear rarely shows wear and the motor can be easily damaged trying to get it apart and back together. Without changing the motor gear, the rest of the repair is simple.

You only need to be sure to get the chain reinstalled in correct relation to the limit switches. After the unit is reassembled you will want to run the opener until it either stops in the up position or the down position, then install the chain and door trolley in the proper position.


----------



## Simon96Taco (Nov 11, 2009)

iamrfixit said:


> I have seen that a few times, the chain may have been too tight, have also seen the washer wear into the shaft and spin in such a way that it actually cuts the shaft right off.
> 
> You can buy the gear kit complete with this shaft assembly. The shaft, complete with sprocket and bushing is held in with 3 screws and fits into another bushing below the main gear. Here is a link to the parts. You will have to take the opener down since it is mounted against the ceiling. It's a fairly easy fix. I don't usually change the worm gear on the motor unless I have to. The worm gear rarely shows wear and the motor can be easily damaged trying to get it apart and back together. Without changing the motor gear, the rest of the repair is simple.
> 
> You only need to be sure to get the chain reinstalled in correct relation to the limit switches. After the unit is reassembled you will want to run the opener until it either stops in the up position or the down position, then install the chain and door trolley in the proper position.


Awesome, iamrfixit! Will I also have the take the entire track down or can I just take the motor off the ceiling? It looks like they might be joined together. 

Another Q - can I rest it on top of a step ladder and replace the gearing, or is it all the way to the ground that it will need to come?

Thanks again!
S


----------



## chitownken (Nov 22, 2012)

There are only a couple of bolts that hold the motor to the track. While it would be possible to replace the gear while it is sitting on top of a step ladder, it would be much easier on a table or workbench. Disconnecting and reconnecting the track is really no big deal.


----------



## Simon96Taco (Nov 11, 2009)

Thank you all again. It's now back up and running. I do have a question though, in regards to the wiring - specifically the small push-lock connectors that the wires from the opener and the sensor connect to on the drive unit.

It took me a while to figure out how these connectors work. Apparently you push the orange tab on the bottom with a small screwdrive, put the wire inside the connector, then release the orange tab. It locks down on the wire and holds it fairly well.

However, as you can see from the picture, one of my connector's (the third from the left) orange tabs is broken. This means I can't make the inner part open up to receive the wire. I currently have my wires jammed in and roughly taped against the side of the unit, which works for the time being, but I'm sure will give me trouble.










Anyone know how to open that connector now that the orange tab is missing? Or some other way to force the wires inside the connector as is?

Thanks again,
S


----------



## iamrfixit (Jan 30, 2011)

I'm fairly certain that both of the white connecters are common and are connected together. Strip both white wires a little long, then twist them together and cut them off to length and insert in the remaining good hole. 

Or you may still be able to use the damaged connector. Assuming the clip that retains the wire is not damaged or missing, you should be able to insert the wire without pushing the tab. The wire has to be stiff enough to push the spring, you could either use a short pigtail of heavier solid wire or twist a short second piece of wire with it. If you ever need to remove it again; the wire usually can be removed from the spring retainer by twisting and gently but steadily pulling at the same time, or just clip the wire then strip, twist then ends together and use a small wire nut to reconnect.


----------



## mako1 (Jan 7, 2014)

Most garage door openers that Sears sell are made by Chamberlain.
You're a lot better off getting parts from them.Or one of the online store that sell OEM parts.

http://www.chamberlain.com/parts-and-support/parts-center


----------



## AlphaPilot (Aug 6, 2012)

Those two wires already connected and the two not connected are *not* common. Two wires per sensor. The wires are identified by a stripe along them versus solid white. When I installed sensors, I had to place the striped wires together in their slot with the solid white wires together in their designated slot. If you combine all 4, the door will only close by holding the wall mounted switch.

As Iammrfixit said, the white connectors may be a common. It won't hurt to try that before anything else.

It looks like those are tiny flat-head screws that loosen the plastic bracket. Perhaps the screw can be loosened on tab three, allowing wire to be wrapped under the screw as you tighten it back up. :whistling2:


----------

