Grasp the tube coming from the spring's outer side with a jaw-locking pliers. Back out the hex-head machine screw holding the casting over the majority of the tube with a drill and a hex driving bit.
Release the spring's tension by slowly turning the jaw-locking pliers toward you. Count the number of times the pliers makes a full revolution. Once the tension has been removed, write this number down on a piece of paper.
Back out the two screws that hold the torsion spring in place with a Phillips driving bit. If the torsion spring is held in place with pop rivets, drill out the rivets with a 3/16-inch drill bit. Remove the torsion spring from the awning's cylinder.
Spray a lubricant around the cylinder's opening. Slide the new torsion spring into the cylinder. Line up the spring's screw holes with the cylinder's screw holes. Use a drill and Phillips driving bit to drive the supplied screws through the screw holes. If the awning uses rivets, use a rivet gun to secure the rivets in place.
Clamp the jaw-locking pliers onto the tube extending past the spring. Twist the pliers around the tube the same number of times you had untwisted the previous tube in Step 2.
Slide the casting over the tube. Secure the casting in place with the hex-head machine screw you removed in Step 1.