Garage door jerks when opening

[dchou4u]

Hi, I have a 10 year old garage door opener. When the garage door opens, sometimes it jerks the door at the start, but the door opens fine. There are also few times when we close the door, the door will bounce off the floor and reopens by itself.

Does it sound like a bad tension in the spring, or something else?

Thanks

[professorpaul]

A couple of things come to mind...

1. Check is all bolts, hinges, tracks, etc., are tightened up. These do work loose.

1. Check that track and chain or drive system is properly lubricated. Any light grease will do. Something that won't drip or run is better. A "white" non-migrating lubricant.

2. Check opening/closing forces.. There are adjustments on the motor. Likewise for overtravel.

I do a check for those items once a year on my garage door lift, FWIIW.

If the two items above don't do the trick, then you might want to call in a garage door outfit. I have replaced springs, but that can be more than a little bit tricky.

[LouB]

And dangerous!

Lou

[Winston]

Both symptoms are common to the same cause.

Check your opener's limit switch, would be my advise. Sounds like settling has caused the door to close 'earlier' than it had when the opener was first installed.

You need to move the limit switch back a taste so that the door closes securely yet does not 'load up'.

--Winston

[Dennis]

You mean that when the door is closing, it went further than it should and hit the floor too hard and thus causing it to reopen?

How about the jerking when it opens?

Thanks

[Paul Oman]

In my case it was the cable that raises/lowers the door. Cable was not rolling up nicely on the drum so when cable wrapped/unwrapped it jerked the door around.

paul

[HeyBub]

Slack in the chain? Skipping sprockets?

[shellyf]

The cause in my case was that the rubber on the bottom of the door was sticking to a relatively new concrete stain which was applied to the floor. I applied a strip of duct tape to the floor in the area where the rubber was sticking, and the problem disappeared. I was told to apply some paste wax to the rubber, but I never got around to it. hth

[Hipupchuck]

The chain is connected together with a spring for safety. The door appears to be sticking, then releasing stretching the spring as it should. Check the track and around the door. Operate it by hand to help find out where it is sticking.

[Winston]

Yes. The 'down limit switch' is telling the opener that the door had not closed. So the opener has only one choice; that is to treat the garage floor as an obstruction, triggering the re-opening. Your 'down limit switch' is adjusted on the 'edge' of working properly. Sometimes it forces the door on to the garage floor, sometimes it sees the floor as an obstruction and re-opens.

Does this sound familiar?

Buildings move as they settle. Doors jam. Windows stick. Same thing here. You can't jack the settled side of the door jam back up, so you readjust the opener.

Both of these symptoms are consistent with the same cause. (I don't know if I mentioned that.)

Watch the opener carefully as it closes the door. You will see it bend a little as it stores the energy it took to force the door on to the garage floor. When you open the door, some of that energy returns in the form of a rebound.

That is the jerk you see.

Here is an Experiment:

the position of the 'down limit switch' (with a magic marker) on the track. (Then photograph it with your digital camera.) Loosen the 'down limit switch' and slide it back, toward the opener motor a couple inches. Tighten it in this new position. You should see daylight under the garage door after it closes, but the jerk will disappear. You will find a place on the arm of the opener for the 'down limit switch' that will allow the door to close securely yet not rebound as it does now. Just move the switch to that position and tighten it in place.

You have nothing to lose here. If the experiment doesn't work in this manner, you can slide the limit switch back to it's previous position and you are back where you were.

--Winston

[Winston]

Dennis didn't write:

You are welcome, Dennis. I'm happy to help out.

--Winston