If your torsion spring is damaged, loosen the set screws on the winding cone.
Caution: If the torsion spring is still coiled, then do not touch the set screws on the twisty cone, then you need Spring Replacement Riverside. Do not touch the bolts that protects the stationary cone to the spring hook bracket. Once the winding cone is loose to slide on the shaft, slide the two parts of the spring rear together. The coils must be touching, and there shouldn’t be a gap anymore. As with the uncoiled spring above, measure the length from the initial coil on one end to the terminal coil on the other. Do not add the cones, but include the coils that are above the cones and you will require Spring Replacement Riverside.
Spring changing in garage door
About the tools needed you should know that you should ALWAYS wear eye protection safety glasses, you need to keep them protected in case anything flies into your eyesight like dust or dirt from the old spring. The next thing you might be wanting to want to use are the proper pair of winding bars that have a 90 degree angle on its edge and it not curved. A curved winding bar could slip off of the socket while trying to wind or unwind the spring and cause a serious accident. The next thing you will need are a pair or vice grips to manage the cables, grabbing them with your hands can be done too but it is not recommended because it is not very safe. Next thing you will need are two wrenches: a 7/16” wrench and a 9/16” wrench. The last thing you will need is a ladder to get on and reach for the high tension bar to which the tension spring is attached.