Tie the extension spring to the roller track then detach the cable from the bottom bracket with a pair of pliers.
How to install double garage door extension springs.
If the extension springs are not the same length open the garage door and change the location of one of the s hooks so that when you close the door both springs are the same length.
If both springs are the same length the garage door should be level across the floor.
A problem with the spring tension could cause the door to open or close unevenly improperly or at the wrong speed and adjusting the springs will likely solve the problem.
Garage door springs offset the weight of the door and allow it to open and close with ease.
Following are the steps necessary to replace one or more of these springs while taking safety precautions.
If the spring breaks near the stationary cone a large portion of the spring spins loose with the winding cone secured to the shaft.
Release the tension on side mounted extension springs by lifting the door and locking it in place on each side with a pair of locking pliers.
Many manufacturers have cut costs by using a single spring on a double wide 16 steel garage door.