Garage Door Extension Spring
Extension springs are the long springs running along the horizontal tracks on each side of the door, parallel to the ceiling. They stretch as the door comes down and pull it back up. They are found mostly on older and lighter Florida doors, and when one breaks the door goes crooked, drags on one side, or refuses to lift. Replacement runs $150 to $350 installed, always in pairs, and any extension spring without a safety cable through it should be treated as urgent.
Covered by Garage Door Spring Replacement · from $150
An extension spring works by stretching rather than twisting. When the door is down the spring is at full extension and holding the most energy, and as the door rises the spring relaxes. Two springs, one each side, share the load.
The important safety point is the containment cable. A steel cable should run through the middle of every extension spring and anchor at both ends. Its only job is to catch the spring if it snaps, because a spring under tension that lets go becomes a length of steel travelling across the garage at speed. Older Florida installations frequently have no containment cable at all, and if yours does not, that is worth fixing whether or not the spring has failed.
You can inspect these from the floor. Stand back with the door closed and look along each track. A broken spring is obvious: it has separated, gone slack, or one side sits visibly longer than the other.
How to tell this part has failed
- The door lifts crooked, with one side clearly higher than the other
- One spring hangs loose or has visibly separated
- The door binds and scrapes in the track on one side
- The opener strains, or the door stops partway
- A loud snap followed by the door dropping or jamming
- One spring looks noticeably stretched and longer than the other
Why it fails in Florida
Like torsion springs, extension springs are rated in cycles rather than years, and they arrive at the end of that rating together because they have done the same work.
A door running on extension springs is usually an older Florida door, which means the springs have often had twenty or more humid summers. Corrosion pits the steel and the spring fails at the pit rather than at the cycle count.
Uneven wear compounds it. Once one spring weakens the other carries more than its share, so the second failure follows the first much faster than the first took to arrive.
Can you do this yourself
No, do not attempt this
Not a homeowner job. An extension spring at full stretch with the door closed holds enough energy to cause serious injury, and the springs, the pulleys and the cables all have to come off and go back in the right order and at matched tension. If your springs have no safety containment cable running through them, say so when you call, because we fit those as part of the job.
Starting prices for a standard single door. Your final price depends on the door, the model, the wind rating a replacement needs and what we find. You get a written quote before any work starts.
Have a technician bring this part
Leave your details and we call you back to confirm the part, the price and a time. The technician arrives with it on the truck.
Garage Door Extension Spring
Not sold separately. Price shown is fitted, by a technician who brings the part.
(561) 897-9930Frequently Asked Questions
What is the safety cable inside the spring for?
It contains the spring if it breaks. An extension spring under load that snaps without a cable through it travels across the garage with real force, and the cable turns that into a spring hanging harmlessly on a wire. Many older Florida doors were installed without them or lost them during a previous repair. We fit them as standard and we will tell you if yours are missing.
Should I convert to a torsion system?
Often it is worth pricing, and we will tell you honestly whether it is worth it on your door. Torsion is safer, lasts longer, balances better and is quieter. It also costs more because it needs a header bar, brackets and mounting, so on a small light door near the end of its own life the answer is usually to replace the extension springs and spend the difference elsewhere.
Can only one extension spring be replaced?
It is physically possible and we do not recommend it. Both springs are the same age with the same cycles on them, so the second failure is close behind. Worse, a new spring next to a tired one pulls unevenly, and the door then wears its rollers and cables faster on the weaker side.
