Hello! Last week the door opener stopped working, I discovered that the plastic gear inside was extremely worn out and shredded apart. I ordered a new kit and plan to replace it when it arrives.
My question is though: the door quit working half way up, I pulled the release cable but in order to use it manually I needed to get the trolly out of the middle of the tracks. When I begin putting it back together, do I need to match where the trolly was, or could I position it fully open or closed?
Thanks!
It will prob move slightly during the repair anyway. I just fixed my neighbors 2 days ago. It was in the down position when I got it, so I marked the track and put it back as close as I could, he had to just tweak the positions after re-install.
The instructions will explain set the thing up. Basically, you just run it in the down direction til it stops, then put the chain and all back on.
If you are doing it with the opener still up (just resting on the ladder) it will be easy to hook the door back into the trolley in the closed position then hook up the chain.
Btw...the distance from the end of the rail to the front edge of the trolley was 9.5 inches for his, yours would probably be close to that depending on how your arm is set.
So I should just be able to press the button and see which way it spins and when it shuts off it will either be fully up or fully down?
I'll look at the instructions as well once the parts arrive (hopefully today!)
Yes...looking down from the top, a clockwise turning cycle will be in the fully down position (based on the limit switch setting). It may still require slight tweaking once hooked up.
Did you get the full kit or just the big gear? I always get the full kit since it has all new bushings and such.
Here's some reading while you wait for the part. Relacing plastic gear in Lift Master
One person put simple instructions for just the big gear if that's what you got. Not sure how good they are since I used the full kit.
I got the full kit, the sales person said it came with all the gears, bushings, and some grease. It was only about 40 including shipping too.
I'll take a look at the instructions you posted as well. I watched a video on YouTube and it looked pretty straight forward, my main concern was that it stopped in the middle and I had to move it to still use the door.
$40? That was $13 more than I paid on Amazon w/free shipping, though I see they are up to about $29 from the same supplier now. Did you get it from Sears?
Main hint...as you disassemble it, take pics or make drawings and keep all the parts in order.
It may be kind of tough to take the gears off the shaft, the grease hardens to almost a varnish. Careful prying with a screwdriver will ease it off. Clean the shaft with acetone or similar and the new one will go on pretty easy. Make sure everything is seated back in the original positions and the interrupter wheel is fully seated. If you remove the little rotation sensor board per the instructions (I think you HAVE to to get the motor out) be careful with the little tabs that hold it in place, if you snap one off you'll have a bigger issue.
Took me about 45 min or so but I had the owner as a second pair of hands and the whole unit down and on my workbench.
The same thing happened to me and I took a picture of my Sears lift as well. I will provide a picture for all that are curious. I need to replace mine
Yea I got it direct from sears, only took about 3 days to get here. It started by me calling to see if they had one in a store in the area but they didn't so I just said ill get it shipped in.
Got her all done, worked out great. I just hit the button let it return to the closed position, then threw the chain on and adjusted it till it opened and closed right.
I think the chain was in a different position before but I don't think it's an issue as I re adjusted it to open and close post repair.
Thanks for your help!
Should I just get the replacement gear for $6 or the gear with sprocket kit for $23..?
Do the whole kit. And make sure the door is operating correctly, badly adjusted/damaged doors and lack of grease it what causes these to fail.
ive never replaced the worm gear. there is zero need.
i do suggest replacing the brash bushing that centers the gear/sprocket just above the small limit gear.
if youre worried about limits, vise grip the chain to the t-rail just in front of the carriage.
The worm gear gets a lot of melted crud from the drive gear when it fails. Yes, it is a harder material than the big gear, and you could probably clean it all out, but why buy a kit to get all the bushings, gears, and such, and not use all the parts?
The kit I use comes with a new chain drive gear, shaft and big gear (sprocket?) pre-assembled. As well as all bushings, wave washers, pins, thrust washers, etc, etc. Sure...don't need the stuff included for a belt drive...but I'll use everything possible that I paid for.
Just my opinion......
True but you can just buy the gear (pack of 2) for $6 vs the kit with 1 gear for $20+ Chamberlain Sears Craftsman Liftmaster 41A2817 Gear Kit - Amazon.com OR Chamberlain LiftMaster Sears Craftsman 41C4220A Gear Sprocket Assembly Kit - Amazon.com OR 2 Pack - Drive Gear for Sears Crafsman Liftmaster Chamberlain Garage Door Openers 1984-Current - Amazon.com
not a fan of the gear only. not only are they hard to do if you havent done them a lot, a key bushing is not being replaced.
Thank you, this is the answer I am looking for.
I replaced the sprocket but I skipped on the worm gear because it looked fine and just needed a cleaning. As soon as I hooked everything back up, with the door down along with the part with the red handle (slid that back to hook it up to the door) I hit the button and it got all jammed up. It torqued the railing for a moment until I could release the pressure.
My question is how do I recalibrate or reset the opener so it knows its it's fully up or down and not where it was when the gear finally went?
I tried adjusting my up and down limits but it doesnt seem to change where the trolley stops. The up limit stops about 3/4 up and the down limit slams into the stop, creates slack in the chain and reverses. Has anyone had issues after changing the sprocket with the limits not working?
Tags: replacing, gear, craftsman, garage, door, opener, fully down, just gear, worm gear, closed position
