Like every part of the house, over time, the springs on your garage doors may break or lose tension. Replacing these high-tension springs is a challenging and potentially dangerous project, so you should only attempt it if you are a serious do-it-yourselfer. Different garage doors have different spring types and replacement techniques, so first determine what type of spring or springs you are working with. For instance, your garage door may operate with extension springs, tension springs or a combination of both. Double garage doors with overhead springs use torsion springs mounted to a central bracket in the middle of the door and can be used to help you understand the general principles for replacing garage door springs.
Disconnect Your Garage Door's Power Source
Before removing any springs, you'll first need to disconnect the garage door's power source. Start by closing the garage door and unplugging the power cord to the garage door opener. If the opener is hardwired to the building's electrical system, remove the opener's fuse or disconnect the circuit breaker for the garage area and disconnect the opener from the door. New models usually have a neutral position you can place the opener in while replacing the springs, while older models may require you to disconnect the opener altogether.
Gather the Correct Springs
While it may sound unnecessary, take a minute to ensure the replacement springs and the old springs are the same size. Measure the length and diameter of the old springs while in place, and compare with the new ones. Mark the location of the spring cone with a marker or chalk.
Unwind the Old Springs
You'll need to remove the old springs by first unwinding the springs to release the tension on the garage door's bar. You'll need two winding bars to complete this task. Insert one winding bar into one of the winding cone holes. The winding cone is the circular part at the top of the spring. Ensure the winding bar is at least 18 inches and the right diameter for your winding cone. Unscrew the spring's setscrew with a wrench. Pull down on the winding bar. Insert a second winding bar into another hole while still holding the first bar in place. Release the first bar, and pull down with the second bar. Repeat until the spring is unwound and there is no tension on the bar.
Remove Bolts and Drums
Once the spring is unwound, remove the bolts that hold the stationary end of the spring to the anchor in the center of the door. Loosen the setscrews from the cable drums at the end of the garage door. Remove the drums, and slide the springs off the garage door bar.
Slide on the New Springs
Slide on the new spring. Ensure the side with the bigger hole, the stationary side, goes in first. Reassemble the cable drum. Repeat the process for the other spring. Insert the garage door bar into the cable drum. Tighten the garage door shaft by twisting the garage door bar.
Fix Spring to Center of the Door
Fix the stationary end of the torsion spring to the center of the door, and tighten the bolts. Make sure the stationary cone is flush with the anchor's bearing plate.
Wind the New Spring Onto the Door
Wind the new spring onto the garage bar in the reverse way you unwound the old spring. You'll need both winding bars for this task, as well. Insert the first winding bar and push up. Insert a second bar while holding the first bar in place, and then push up. Repeat until the spring is wound and reaches the mark you made previously. It will generally take seven and a half turns to wind up a torsion spring. Repeat the process for the other spring.