When a spring breaks on a garage door an immense amount of energy being displaced. Torsion springs are mounted over the garage door and they have a shaft running through the middle. When they break, the spring unwinds in less than a second and creates a loud noise due to the coils spinning on the shaft. Based on customer feedback, it can be quite startling.
If you need to leave the door open until you can make repairs, block the door track on both sides so the door can't move, and unplug the garage door opener (if you have one). If you want to close the door, you can try closing it with the opener, making sure there's nothing in the door's path in case something goes wrong. However, this will put some strain on the opener. Alternatively, you can have a few strong helpers hold the door while you disconnect it from the opener and carefully close the door manually—again, it will be very heavy. https://www.youtube.com/watch?v=Z_eZc-kh40c&hc_location=ufi
On one-piece doors with side springs, you open the door to relieve the spring tension, and simply swap out the springs on the opener-arm mechanism; there are no cables or pulleys to deal with, and the springs have internal safety rods. Some doors have tensioners that maintain moderate tension when the door is open all the way, and on these you'll have to loosen the tensioner in order to remove the spring.
One spring or two springs? If you have a two-car garage, it’s industry’s best practices to replace both springs, even though only one may be broken. When one spring breaks it makes sense that the other spring will most likely break shortly thereafter. Why pay for another service call? Additionally, since springs need to have the same tension, replacing only one is not effective.
10.8 After the cone reaches the mark, continue pulling the bar off the garage door and back toward the middle of the door with your left hand. Tighten both set screws 1/2 to 3/4 turns each after each screw first meets the shaft. This is the point at which you will feel the screw meeting resistance. If the garage door spring snakes after tightening the set screws, repeat the process and stretch the spring half as much as before. Residential torsion springs are stretched 1/8" to 1/4". Larger commercial and industrial overhead garage door torsion springs are stretched as much as an inch. http://www.youtube.com/v/Z_eZc-kh40c&feature=kp
7.4 Check to make sure the torsion hardware is secure. If needed tighten the lag screws that attach the spring anchor bracket to the header. If loose, replace with longer or thicker lags. Brackets for doublewide wood doors should have two lags on the bottom, because when the springs are wound the spring torque pulls the bracket from the bottom. Never touch these when the springs are wound. One of my customers removed the screws when the springs were wound. He broke his arm in 14 places and almost died. He spent a month in the hospital.
My experience with Overhead Garage Door was exceptional! They were friendly and fast! I didn’t have to wait days to hear back from them and their prices were far better than that of their competitors top article. I would highly recommend Overhead Garage Door to anyone needing assistance with their door and especially if you’re in the market for a new one!