Adjusting an out-of-balance garage door
With time, the cables and springs on a garage door stretch, and the door can become dangerously out-of-balance. The usual problem is a door that closes too quickly— endangering your feet, your children, or anything else in its path. The door can also open too quickly, which can damage the door or your shoulder. A properly balanced door remains stationary when it’s opened 3 to 4 feet. When you open or close it, it should come to a gentle stop. If it slams down, or closes and then reopens slightly, you’ll need to adjust the spring tension.
BE CAREFUL OF THE SPRINGS - Springs can cause injury if released suddenly. Prop the door open to relieve tension on the springs before you attempt to remove them.
1 BEGIN WITH THE DOOR ABOUT 3 FEET ABOVE THE GROUND. Move it up and down until you find the point where the door remains stationary when you release it. If that point is more than U feet or less than 3 feet above the ground, you need to balance the door.
2 MAKE ALL ADJUSTMENTS WITH THE DOOR OPEN. This takes the pressure off the door springs. Prop the door open with a ladder to make sure the door won't close accidentally while you're working on it. If your ladder isn't tall enough, attach C-clamps in the door track to hold the door in place.
3 MAKE SURE THE SPRING IS COMPRESSED COMPLETELY, AND THEN REMOVE IT FROM THE TRACK HANGER. If the door was closing too quickly, move the spring to the next higher hole on the bracket. If it was opening too quickly, move it to the next lower hole. Move both springs and retest the balance.
4 CLOSE THE DOOR AND CHECK WITH A LEVEL TO MAKE SURE THE DOOR COMES DOWN EVENLY ON BOTH SIDES. If it doesn't, adjust the spring tension on each side of the door until it does.
5 IF YOU NEED TO MAKE FINE ADJUSTMENTS, YOU CAN ADJUST THE LIFTING CABLE INSTEAD OF THE SPRING. The cable is attached to the door and runs to an S-hook that attaches to the track support. With the door propped open, take the S-hook out of the support and tighten or loosen the cable as needed.