I know everybody says garage doors are simple, but my simple mind can’t seem to sort anything my garage door.
Issue: I left my lumber cart sitting directly under my open garage door and got working on a project. When I was finished, I went to shut the door, and SUPRISE the door slamed the lumber cart. (The piece of 16/4 quartersaw oak wasn’t hurt..)
No big deal, I think. I move the cart and try again to shut the door. Met with only the empty sound of a jammed motor. I closed the door manually and then examined the opener.
Two sprockets, one large and one small (small is the drive). Chain is off both of them. With some fiddling, I got the chain back on both and tried the door again. Initially, smooth sounds and then the whole T-track assembly started bowing towards the ceiling and the motor jammed again.
What gives here? Is there an issue with the chain? System alignment? (This is 10 foot door and my full-size truck fits only with the mirrors folded in.) The T-Track didn’t look exactly straight, but I think it’s always been that way.
I’m really not sure about this one and feel stupid for asking. Everything on the web makes it so easy.
Patrick
Edited 4/24/2007 8:18 pm ET by Corrib
Edited 4/24/2007 8:18 pm ET by Corrib
Replies
There's a mechanism inside the opener that measures how far up or down the door is, usually by running a nut of sorts up or down a turning screw geared to the sprockets. This is what ultimately tells the door to stop moving.
You need to disconnect the chain from the gears and then run the opener until it's all the way up or down, then reconnect the chain aligned for that position.
You also need to adjust the force adjustments. Apparently they were screwed down tight (door out of balance perhaps?), causing the chain to pop off before the unit stopped or reversed, and causing it to sit there stalled with the bar bowed rather than stopping.
The force adjustments should be adjusted so that you can easily reverse the motion of the door with the force of your hand.
Next time it might not be a piece of 16/4, it might be a small kid.
DanH,
I didn't see any places to make adjustments or mechanisms that would measure how far the door was open or closed.
There was a sticker regarding the direction of "force adjustment", but I couldn't find a nut or screw. Is it possible that I'll need to remove the cover to make these adjustments? (The opener was installed long before I owned the house, probably mid 80's and seems like it's gotten worse over the last 3 or 4 years)
As far as chain alignment, how would one know whether the chain and drive unit were in the "up" or "down" position?
Thanks, I certainly appreciate the help.
The locations of the adjustments vary. In some cases you may need to remove part of a cover, but you shouldn't need to take the entire cover off -- they should be reasonably accessible. Note that they may look like normal screw heads (and, in fact, someone may have "tightened" them at some point). (On mine they are on the sides of the unit, near the very top, partly concealed by a bump-out in the cover below them.)There should be a total of four adjustments -- two for travel and two for force. They may not all be together (probably not), and they may not all look alike. But they ARE there. They should be labeled somehow, but the labeling may be cryptic.To know which position the drive unit is, remove the chain and then observe the motion of the sprockets when you push the button. Figure out from that if the opener is moving up or down. The chain, obviously, is "up" if the part that connects to the traveler arm is positioned mate with the arm when the door is in the "up" position.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
It sounds like you might have a pre 1984 Liftmaster/Chamberlain/Sears opener (Also sold under some other brands).
I think that is the date.
The older ones had a small sprocket driven off the the motor via a belt.
Then there was a larger idler sprocket that was allowed to move sideways when one side of the chain got tight. That move it agains a spring to trip the overlimit force.
The over limit force was set by a screw that pulled out the spring and there was one on each side of the opener near the top.
That feature on mine wore out LONG, LONG AGO.
So I am familar with the chain jumping the sprockets.
If you loosen the threaded end on the chain at the trolley it makes it eaiser to thread back on. Then tighten before doing anything else.
Unless you ran the opener with the chain off or completely took the chain off then you should not be that far off. What is happending is that the trolley is hitting or it is trying to close the door 2" below the floor.
Then remove the cover and there is a thread shaft that runs with the opener and too cames run up and down to trip the switch.
There is bracket that keeps the cams from rotating. Remove that bracket and you can manually scew the cams.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
What brand is the opener?
It's a Sears, looks like it's from the eighties.
Yeah, I think the force adjustments are on the sides, near the top. You probably do need to remove the cover to reach the travel adjustments. But you don't want to touch the travel adjustments until you get the chain back in sync.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
Thanks for all the help on this!
The primary function of the door is make it easy to load plywood onto my panel saw, so everybody's helping me get back to woodworking as well...
Anyway, I'm going to look at this tonight. One final question: my t-track has a slight bow from left to right. Do I need to fix this first or is it with the margin of error?
Thanks!
I doubt the bow has anything to do with it..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
No biggie. So long as the track isn't bowed so badly that it causes binding, you don't need to worry about it.While you're at it, though, the slider on the T bar was probably last lubricated during the Reagan administration. Throw a little grease on the thing (between slider and bar) before you button it all up. (Wait until then, though, so you don't get it all over everything as you're working.)
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
I must have thrown away my old Liftmaster manual.But I did some work on an old house that had 4 different generations of opener manuals so I grabbed all of the old ones.Have one for a Sears (139.652001/652101/652400) which is identical to my old Liftmaster and must be similar, if not identical to yours.It is shipped with the opener in the down position.Then the when the chain is installed the there is a hole in the t-bar 4 1/2" from the door end.A screwdriver is placed in that hole and the trolley is slide against it (the door end).Then the chain is wrapped around the door end idler sprocket, then around the two on the opener and back to the trolley.That syncs the trolley with the opener head. There is also some adjustment with the links in the arms to the door, but since you did not change that it does not need changin.Then for travel adjustments remove the cover and the T-shapped retrainer bracket.Then you can screw the limit nuts.You need to change them by one full rotation.One full rotation equals 3" of travel.And don't test it without puting the retainer bracket back.TOP NUT - DOWN limit -
turning nut downward increases the down limits (I think that means the door is higher, but not sure with the wording).
turning nut upwards decreases the down limits.BOTTOM NUT - UP LIMIT
Turning nut upwards increase up limits
turning nut downward decrease up limits..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.