I have a Craftsman automatic garage door that came with the house. A few days ago, my wife informed me that the garage door was "making funny noises". Since we'd just gotten home late at night, and she mentioned it after we'd headed off to bed, I figured I'd check it out in the morning. Well, the next morning, she got into the car, hit the button, and the cable snapped. It had worked its way off of the pulley and had frayed and finally snapped (this had probably been going on for some time, explaining the noise). I disengaged the safety latch to raise and lower the door manually until I could get a replacement cable.

An image of the chain / cable. The cable I replaced is toward the front

Well, I got the cable and installed it, but it's still not working. When I push the button, the trolley moves forward about three inches, stops, then moves backwards to the restraining bolt and stops. Right now, the cable is not connected to the door itself, as it's got the trolley too far back to connect. I loosened the chain using the bolts and we tried it again. It again moved the trolley forward a few inches, then just kept pulling it back until it was at the farthest position. The chain from the trolley to the sprocket is taut and the trolley is pulled back too far to hook into the door (normally, it would do so when it moved down to the door, but it's not getting that far).

Things which I've considered:

  • The sensors - I cleaned them off and verified that they're lighting up fine. I also tried raising the door manually as far as it could go to verify that the lowered door wasn't somehow tripping them.
  • The chain - I considered the possibility that I messed something up when putting the chain back on (it had fallen off of the sprocket after the cable snapped. But I think that this is simply the position that it wound up in after attempting to reel in the cable after it snapped, there in the upper position.
  • The cable - I checked to be sure the cable wasn't catching on anything. It is a little bit long at this point, but that end of the cable goes towards the motor anyhow, and it's not catching on anything.

I'm pretty close to just calling a repair guy, but I figured to see if I'm missing anything obvious. This garage door was working before the cable snapped and I tried replacing it.

  • The cable that broke was it connected to the spring that balances the door? If this is not tensioned correctly the opener will not have the power to open the door.
    – Ed Beal
    Commented Oct 10, 2016 at 8:42
  • @EdBeal: Actually, that one that connects the trolley to the chain. It seems to be a standard Craftsman thing, the trolley is moved by something like a bicycle chain, but about half that length is a steel twisted cable. I'll add an image to the question. Commented Oct 10, 2016 at 10:15
  • That might be a tension cable that helps the drive detect when it hits something but that is a guess what is the model and I will try and help find info on it.
    – Ed Beal
    Commented Oct 10, 2016 at 13:07
  • I looked up 2 different models both have open and close tension adjustments. I wouldn't think this should have changed but maybe the chain is tighter now and the down force pot needs adjustment. When the door detects an object befor the limit mounted on the chain it will stop and back up according to the online manual
    – Ed Beal
    Commented Oct 10, 2016 at 13:34
  • My understanding was that those settings were more or less fine adjustments, which makes me a bit skeptical. That said, the idea that the chain might have slipped further than I thought kind of makes sense to me, so I will probably try adjusting the chain to have the trolley further forward to see if that helps. Either that or just run through the install procedure from the start to start at Ground Zero... Commented Oct 10, 2016 at 16:29

1 Answer 1


I have solved the issue. I unplugged the machine and moved the trolley to the end of the rail, as would be done during installation, and then let the door run. The trolley acted just as it ought to and my garage door is opening and closing, saving me a ton of money on a garage door mechanic. I am assuming, at this time, that the chain slipped up when the cable snapped, or that somehow the unit "reset" itself to thinking that the trolley was at the end.

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