This gives the appearance of a broken chain or belt.
Garage door opener sprocket broke off.
Located at the top of the motor unit the gear and sprocket assembly drives the chain that opens and closes the garage door.
Eventually this will cause the sprocket to snap off.
One of the most common repairs on a liftmaster garage door opener is a broken gear sprocket.
Sprocket is at the end of the opener rail closest to the garage door opening.
If the gear and sprocket assembly breaks the motor runs but the door won t move.
Chain driven garage door openers should have some slack in the chain for optimal performance.
Over time though this slack can increase or the gear and sprocket assembly can wear and the chain may pop off the sprockets.
You can put the chain back on your automatic garage door opener using a simple adjustment mechanism.
This was a craftsman model 139 53976srt.
This is a video on how to change the gear sprockets in a craftsman garage door opener.
A new front sprocket costs about 150 200 include the labor to install it.
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.
This diy repair guide explains how to replace the gear and sprocket assembly on a chain drive garage door opener.
This is the part that connects the motor to the chain or belt.