Liftmaster Formula I.
When I hit the button the motor makes noise but the belt doesn't move. The
door moves on the track freely when I lift it manually. Examining the belt
I see the rubber has separated near the motor and only the steel belts are
visible. There is maybe an inch or two of slack in the belt when I pull on
it. This belt seems to be the problem to my untrained eye. Is this
something I can fix on my own?
On Sun, 15 Nov 2015 16:50:21 -0000 (UTC), badgolferman
Look at the trolley and be sure it is not jammed into the back end.
You can take the belt off to break the tie but if it is loose you
should be able to see if it is the motor or the driven pulley that is
My bet is the trolley missed the stop switch and crashed into the
bumper so hard it jammed. Sometime you can rock the door while someone
hits "go down" and break it loose.
On Sun, 15 Nov 2015 20:35:42 -0500, Stormin Mormon
Until the gears "ride up" and jam. Then nothing moves easily (except
the motor when the teeth come off the belt) He sais he hears a
whirring sound - that's the motor running against the toothless drive
On 11/15/2015 3:57 PM, email@example.com wrote:
He still seeks clarification of a working motor and has stated he
doesn't want to replace the belt and gear to discover the motor is
fried. Allowing the motor to run without tension will confirm his concern.
On Sun, 15 Nov 2015 20:39:03 -0500, Stormin Mormon
Common failure on Chamberlain / Liftmaster openers. They are supposed
to be greased - when the grease goes, so do the plastic gears -
particularly when they get to be over 20 years old (and I'm thinking
that one is pushing 30)
On Sun, 15 Nov 2015 16:51:36 -0000 (UTC), badgolferman
If the motor runs and the door doesn't move, and the belt is chewed
up - I'd spend the couple bucks for a new belt and give it a try.
About 95% chance everything else is OK. The remaining 5% is the chance
something else is badly warn and jammed the thing up, causing the belt
Here are some pictures:
Looks like the gear is stripped and the belt is bad. How can I
diagnose the motor?
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