Garage Door Spring Broke: What Happens Now?

Worth two minutes before anything else, because a heavy door and a broken spring aren't automatically the same thing. A door can get heavy from a spring that's fatigued but intact, from a cable that has slipped, or from hardware that has gone stiff enough to add real drag. Those go different places.

The good news is that a broken torsion spring gives you the least ambiguous symptom in the whole trade. There is no interpretation required. Either there's a gap in the coil or there isn't.

How you can tell: A break shows as a clean separation in the wound coil, usually an inch or two, with both cut ends visible and slightly sprung apart. Intact coils sit tight against each other along the whole length.

The version you want, if you're going to have one. The door was already resting on the concrete when the wire let go, so there was no weight in the air and nothing had anywhere to fall.

Most breaks happen exactly here. It sounds counterintuitive that a spring fails while nothing is moving, but the wire is under load whether the door is moving or not, and fatigue cracks propagate under static load perfectly well. That's why so many people hear the bang at two in the morning from a garage that hasn't been used since dinner.

Practically, this means you have time. The door is stable. It isn't going to get worse sitting there.

How you can tell: Door on the ground, gap in the coil, and either you heard the bang or you discovered it when the opener refused to lift.

The opener has a force limit, and when the load exceeds it the unit gives up rather than destroying itself. You'll see the door lift an inch or six, hear the motor labor, and watch it stop or reverse.

That's not a fault. That's the opener doing the one useful thing available to it. The temptation is to override it — adjust the force up, hold the button, give it a hand — and all three of those replace a functioning limit with nothing.

Force settings exist to make the opener stop when the door meets something it shouldn't. Winding them up to lift a door with no counterbalance means the same opener will now push through anything else in its way with the same enthusiasm, long after the spring gets replaced.

How you can tell: Motor sounds loaded rather than free-running. The door moves a little, then quits. Repeating it produces the same result every time.

If the motor runs but nothing moves — often with a grinding or slipping sound from the powerhead, or a chain that goes slack and tight without the door responding — the nylon drive gear inside the opener has given up.

That gear is deliberately the weakest link. It's plastic in a metal assembly on purpose, so that when something goes badly wrong the cheap part fails instead of the motor or the rail. On a broken-spring door it usually takes a handful of attempts to get there.

This is the specific mechanism behind the advice everyone gives and nobody follows: running the opener on a door with a broken spring is the fastest way to turn a spring repair into a spring-and-opener repair. It isn't a scare story, it's a sacrificial part behaving as designed.

How you can tell: Motor noise with no door movement, sometimes with white or gray plastic shavings on the floor beneath the powerhead.

Bigger doors — and heavier insulated ones — commonly run two torsion springs. Both are mounted on the same shaft, one on each side of the center bracket, and they wind together as a single counterbalance. They are not a primary and a backup.

So when one breaks, the counterbalance is out of service. The remaining spring is now being asked to offset a door it was never sized to offset alone, and the door behaves as too heavy across its whole width. It does not hang at an angle. It does not lift on one side. Anyone telling you a two-spring door tilts when one snaps is describing a cable problem and calling it a spring problem.

The other thing worth knowing before the truck arrives: replacing both is not our idea, and it isn't an argument about money. DASMA's own consumer safety tips say it outright — “If your door has two springs, replace both, even if one is not broken. This will not only prevent any damage caused by the breaking of the second spring, but also keep your door working efficiently.” The surviving spring has the identical cycle history — same door, same shaft, same number of openings — so it is due, and a second break can take cables, drums or a panel with it. That it also saves you a second call at full labor is true, but it's the smaller reason.

How you can tell: Two springs on the shaft, one with the telltale gap, the other looking untouched. Door uniformly heavy rather than crooked.

Older doors and some lighter single-car doors use extension springs: long stretched springs running horizontally alongside the upper tracks, one on each side, pulling rather than twisting.

The counterbalance failure is the same. What's different is the failure behavior. A stretched spring under load that parts can whip along its own length, which is why the safety containment cable — a steel cable threaded down the middle of the spring and anchored at both ends — exists. Its only job is to catch the pieces. On doors that predate that being routine, or where somebody replaced springs without reinstalling them, there's nothing there to catch anything.

Because extension springs pull on each side independently, this is also the one setup where a single failure genuinely can leave the door sitting unevenly.

How you can tell: No shaft above the opening. Long springs running back along the horizontal tracks toward the rear of the garage, often with a pulley at one end.

Sometimes the spring isn't the only casualty. When tension releases suddenly, the cable drums at each end of the shaft can spin free, and a cable that unspools loses its wrap. You'll see it as a cable hanging slack, or gathered in a loop, or sitting off its grooves at the drum.

It also happens the other way around, which is worth knowing: a door that jams partway and then gets forced can slacken a cable, and a cable off its drum leaves the door hanging unevenly and the spring taking an unequal load. Either order, once both the spring and the cable are involved, the door has genuinely lost its geometry.

This is the state to be strictest about. A door with a broken spring and a loose cable isn't held by anything predictable, and the next movement it makes may not be the one you asked for.

How you can tell: A visible cable hanging loose, coiled on the floor, or wrapped over itself at the drum. Sometimes the door sits noticeably lower on one side.