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.
Springs are one of the primary components in all garage door systems. Torsion springs are usually mounted horizontally over the door opening. As the door closes, cables add tension to the springs and as the door opens that tension is released. The opening of the door causes the springs to unwind in conjunction with the weight coming off the door. This achieves a natural buoyancy. However, as the door moves up and down over time and the cycle count rises, the steel in the torsion springs will grow weak and will no longer be able to create energy or lift your garage door.
Many jobs around the house are fairly easy fixes. It’s relatively easy to clean out your fireplace, clean the leaves from the gutters or repaint a wall. It’s a different thing to replace your garage door spring. It’s careful work that is almost impossible to do correctly the first time. Garage door professionals spend a great deal of time learning how to do it properly, and even the most detailed instructions won’t make you an expert in the span of a few hours. It can be almost infuriatingly annoying at times and is simply better left to professionals.
Slide the left spring onto the tube and add the cable drum. When your new springs arrive, put the new left spring (the 1 with the end facing up and to the left) on the torsion tube, making sure that the stationary cone on the end of the spring faces the center bracket. After sliding the new spring into place, replace the cable drum and insert the torsion bar into the left bearing bracket.