1:52 video with Jacob Swenson
How to Adjust the Chain on a Garage Door Opener
A sagging chain can drag on the door and wear out the opener. Jacob shows how to set the right amount of slack on a chain-drive opener.
What you'll need
- A wrench
- Needle-nose pliers (optional)
Step by step
Check the sprocket first
If the chain hangs low, look at the sprocket on top of the motor. If it's worn, that needs to be fixed instead.
Loosen the lock nut
On the adjustment bolt along the rail, loosen the outer nut.
Tighten the chain
Turn the adjusting nut to take up slack, by hand or with needle-nose pliers.
Leave a little sag
The chain should sag just slightly above the bottom of the rail at its midpoint. If there's no sag at all, it's too tight, so back it off.
Lock it down
Tighten the lock nut again and run the door to check it.
Filmed in 2012. The basics haven't changed, but newer doors and openers may differ a little. Springs and cables are under high tension, so never adjust them yourself.
Door acting up? Talk to Jacob.
Tell us what's going on and get a straight answer and a clear price. $19.95 off any repair for new customers.