Most residential garage doors use a center-mounted torsion spring that provides a counterbalancing force against the weight of the door; two cables, one on each side of the door, transfer the spring's lifting force to the door. These cables are reliable, but corrosion, abrasion caused by rubbing against the rail, or merely old age can cause them to fail. Fortunately, replacing these cables is a relatively easy task for homeowners, and you can perform garage door spring repair yourself in under a half hour. Below are the tools and materials you will need:

Tools and materials needed

• 2 locking pliers

• Replacement torsion spring cables

• Flat-bladed screwdriver

• Stepladder

A step-by-step procedure for replacing the torsion spring cables

Before getting started, it's essential to remember that safety is paramount when it comes to performing work on a garage door. Never work on a door connected to a powered opener mechanism; always unplug your opener or turn off the appropriate circuit breaker at the main panel. In addition, keep in mind that garage doors are heavy and can cause crushing injuries if they fall on you or someone else. Work slowly and deliberately, and don't hesitate to contact a professional service company if you have any doubts about your ability to complete a repair.

1. Purchase replacement cables – for 7-foot garage doors, the standard-sized door found in most residences, you will need cables that are 8 feet, 6 inches in length. Replace both cables on your door at the same time; chances are high that the other cable will be shorter or longer, resulting in an uneven door when lowered. In addition, when one cable fails, there is a good likelihood the other cable will also fail soon.

2. Immobilize the garage door – raise the garage door normally, then detach the garage door from the opener trolley by pulling the quick disconnect handle. Next, remove the garage door opener's power plug from the ceiling-mounted outlet. Finally, apply one pair of locking pliers to the rail just beneath the door on the end where you will be replacing the cable. Be sure the pliers grip the rail snugly and prevent the door from dropping downward.

3. Disconnect the cable from the door – after the door is immobilized, place another pair of clamping pliers on the torsion spring shaft just outside of the cable drum. Locate the point where the cable is attached to the bottom of the door, grip the locking pliers and rotate the shaft about one-eighth of a turn toward the garage door opening to loosen the cable. Once the cable is loosened, pull the looped end of the cable from its mount on the garage door.

4. Remove the cable from the drum – remove the locking pliers from the torsion spring shaft and unwrap the cable from the drum. Be careful not to scratch the door with the cable. Once you reach the end of the cable, remove it from the drum completely by pulling its end from the mounting slot.

5. Attach a new cable to the drum – with the old cable removed, attach the end of the new cable to the drum's mounting slot; use a flat-bladed screwdriver to shove the end into the slot if necessary. Next, wrap the new cable around the drum in a direction toward the garage door opening. Use one hand to hold the cable in-place on the drum while feeding additional cable with the other hand.

6. Attach the looped end to the door – once you have wrapped the cable completely around the drum and have a small length of cable remaining, reattach the locking pliers to the torsion spring shaft. Use the clamping pliers to rotate the shaft until you have enough cable to attach the loop to the bottom of the door. Reattach the cable, rotate the shaft back into position, and remove both pairs of locking pliers. Reconnect the door to the trolley, and plug-in the opener so you can test your repair.