It is now time to wind the new springs, but before doing so, we recommend marking the shaft just beyond the winding cone. This is a final step taken to assure that you have installed the springs on the correct sides of the center bracket. Torsion springs always grow in length when they are wound in the proper direction. If your spring does not get longer as you wind it, you are winding it the wrong direction probably because it is improperly installed.
Tape your winding bars if you have not done so already, not only to assure that you are inserting the bars completely into the cones as you wind the torsion springs, but more importantly to assure that the bar does not slip out of the cone when you stretch the springs at the end. This has happened to me several times. Professionals always stretch torsion springs after winding them because the shaft floats horizontally between the flexible end bearing plates as the door operates. Although this may be as little as 1/4", the binding of the coils as the garage door closes oftentimes keeps the door from closing completely, especially when the torsion springs and bearings are dry.
At this point you will wind the spring. Notice that the end of the spring on the winding cone points up when facing you. You will wind both springs up and counter intuitively as if you are trying to unscrew the winding cones from the ends of the springs. Begin by turning the spring up 1/4 turn until it meets resistance. This is your first quarter turn. Count "one." Next, insert the bar and raise it 90 degrees. Insert the second bar. This is "two." As you wind the spring it should grow in length the thickness of one coil for every turn. The cone should cover your mark after the first couple turns. Many garage door tradesmen mark the torsion springs with chalk or paint, but this often generates confusion.
Raise the second bar 90 degrees and insert the first bar. This is "three." Continue winding. If the spring shortens in length, unwind the spring and switch sides - the springs are on backward. Otherwise, continue winding until you reach a count of "30." This is 7 1/2 turns, which is normal for most 7' doors. Newer steel doors with only one strut on top often need only 7 1/4 turns. On 8' doors count to 34. Each time you insert a bar into the winding cone, listen for the click to let you know the bar is in all the way. Not inserting the bar all the way could cause the cone to explode.
If the spring comes loose from the cone at about 6 turns, you are probably winding the spring backward because the springs are on the wrong sides. Switch the springs. Otherwise, after winding the torsion springs, you will need to stretch the springs and secure the winding cone. First, mark the shaft 1/4" beyond the winding cone with tape or with a file. We stretch the springs because the shaft floats horizontally between the flexible end bearing plates as the garage door operates. Although this may be as little as 1/4" the binding of the coils as the door closes often keeps the door from closing completely, especially when the springs and bearings are dry and need lubrication.
Here you will need to do three things at once. With your left hand, lift the bar just off the top of the door and pull it toward the center of the garage door. While lifting up and back, tap the top of the bar just under the winding cone with your other bar. Pulling the bar back toward the center of the door as you tap causes the spring cone to bind on the shaft and not slip back.
Continue tapping until the cone moves out to the mark on the shaft. Continue holding the bar off the garage door and pulling back toward the center of the door. If the cone slips away from the mark, repeat this step. Keep an eye on the tape to make sure the bar doesn't slip out of the cone. If it does start to slip, rest the bar against the top of the garage door, insert a bar in the next hole and turn the cone up enough to make it possible for you to push the marked bar back into place
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 setscrews 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 setscrews, 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.
Carefully test the setscrews by pulling down on the bar. The winding cone should be tight enough so that when you pull down on the bar, the garage door should begin to lift. If the bar starts to slip when you pull it down, add 1/4 turn to each set screw.