When Good Garage Door Openers Go Bad.
For many years people called to ask me why their garage door opener would not work.
“You can hear the motor run, and sometimes it moves for a few inches, but then it stops!” they would tell me.
Sadly, the only explanation I could give was the nylon (plastic) gears had stripped out and replacement of the entire unit was the most economical solution.
In their own right nylon( plastic) gears are something of a miracle for medium to light duty gadgets.
Reasonably robust, they will serve well for many moons. (Some of the garage door openers I replaced were 10-12 years old.)
Difficult gear configurations are very inexpensive to cast (by the thousands) especially compared to the machine tooling required with metal gears AND they will do (almost) the same work!
The trouble starts when they are overloaded for some reason and the gear teeth strip out.
Then, Houston, we have a problem.
Here for your edification and entertainment is video of one of these stripped out nylon (plastic) gear trains.
It is hard to see the extent of the damage, but notice the shavings on the round horizontal gear
Notice also the motor (and control panel) work perfectly. But the springenwerk is kaput!
If your door opener is of the high end variety it is possible to order replacement parts:
But for the garden variety opener, the price point for a replacement unit is still competitive.
With this video archive of the motor running my next step will be to disassemble the gear train and post some close up pictures to demonstrate just how badly the gears are shredded.
In the meantime, as an example of sudden nylon gear death examine this main gear from another assembly. It came from a pretty handy electric chainsaw-used for clearing brush and miscellaneous firewood chores.
One day the blade hit a knot in the wood and stopped and the motor kept turning and the gear kept spinning and it was instant kaput for the little chainsaw. (Click on Image for high resolution detail)