Springs are used on commercial overhead doors in several configurations. One configuration that is common is the rollup doors in self-storage facilities. These springs are torsional–that is, they twist and untwist to help raise and lower rollup doors. Eventually, the springs snap due to fatigue stress, and must be replaced for the door to operate. A door that is extremely hard to open, and when opened falls loosely over the top bar rather than coiling tightly around it, is a door with a broken spring. One strong person can replace a smaller, one-spring door in under two hours; larger doors will require two strong people.
Set Up and Remove Broken Spring - Raise the door and put the tools, parts and ladder inside. Use the toolbox to hold the door open enough for light and egress. Lightly file the right end (when facing the door from inside) of the roller shaft all around it to remove rust and any burrs. Pull the cotter pin next to the bearing. Sweep accumulated dust and dirt off the door. Lightly lubricate the right end of the roller shaft and the shaft bearing.