How to Make a Chain Tighter on a Garage Door

Close the garage door with the door opener. Once the door is closed, unplug the garage door opener power cord from the outlet in the ceiling. Depending on your ceiling height, it might be necessary to set up a step ladder under the opener head to reach the power cord plug.

Grab the emergency pull rope hanging from the garage door opener trolley, and pull down to disengage the door from the opener. The emergency rope ties to a small release arm under the trolley. When the arm is pulled down with the rope, it disengages the trolley that the door opener arm connects to from the opener carriage that rides on the opener rail.

Move the step ladder under the opener carriage so you are able to reach the threaded adjustment rod connecting the chain to the carriage. The end of the chain connects to the rear of the threaded rod, and the rod inserts into a flange on the carriage. There is a nut on each side of the flange threaded onto the rod.

Loosen the nut pointing toward the rear of the door opener with a 7/16-inch wrench. Once the nut is loose, spin it until it is halfway down the length of the threaded rod. Look at the entire length of chain to ensure there are no twists in the chain. If twists are present, rotate the threaded rod until the chain is straight.

Hold the rear of the threaded rod at the point the chain connects with your fingers. Turn the nut on the front of the carriage flange clockwise with the wrench. This will draw the threaded rod toward the front, tightening the chain.

Continue rotating the nut clockwise until the chain is halfway between the top and bottom of the door opener rail. Once the chain is tight, spin the rear securing nut back toward the flange. Once the rear nut is against the flange, tighten it with the wrench.

Pull the emergency rope toward the rear of the motor to engage the release arm. Lift the garage door as necessary until the trolley locks over the carriage. Plug the garage door opener power cord back into the outlet.