If the gear and sprocket assembly breaks the motor runs but the door won t move.
Garage door chain sprocket replacement.
This diy repair guide explains how to replace the gear and sprocket assembly on a chain drive garage door opener.
Over time the sprocket s teeth can wear and the chain may jump or skip when the opener raises the door.
Chain drive garage door openers have a sprocket that is attached at the top of the motor.
Step 1 turn off the power.
This was a craftsman model 139 53976srt.
Amazon s choice for craftsman garage door sprocket replacement for liftmaster 41c4220a gear and sprocket kit fits chamberlain sears craftsman 1 3 and 1 2 hp chain drive models 4 8 out of 5 stars 1 216.
This is a video on how to change the gear sprockets in a craftsman garage door opener.