Loud bang, then the garage door won't open: what broke?
By American Garage Door Solutions Updated
A loud bang, then a stuck door, usually means the torsion spring broke, says Daly City's American Garage Door Solutions. That spring carries the full weight of the door, so once it snaps the door gets too heavy to lift by hand or by opener, and it needs to stay shut until a technician checks it.
What not to touch: the torsion spring and the manual release cord, since pulling the cord lets an unsupported door drop fast once the spring has failed.
A bang like a gunshot, then a door that will not budge, is one of the most recognizable failures in a garage. It almost always points to the torsion spring mounted above the opening, not the opener itself. Knowing what that part does helps explain why the door feels bolted to the floor and why forcing it is a bad idea.
The torsion spring is what lifts the door, not the opener
Above most sectional garage doors sits a metal shaft with one or two torsion springs wound tight around it. A torsion spring carries the weight of a sectional door, and the opener only has to move the door, not hold it up. When the spring breaks, that balance disappears instantly, usually with a loud bang as the coil lets go.
Once the spring is gone, the door can weigh well over a hundred pounds with nothing supporting it. An opener motor is built to nudge a balanced door along its track, not to lift dead weight, so running it against a broken spring strains the gears, the drive belt or chain, and the mounting bracket.
A dead opener or a slipped cable can look the same from the kitchen
Not every stuck door is a spring. Each lift cable winds onto a drum at one end of the spring shaft, and if a cable jumps its drum, that side of the door drops and the door can jam at an angle instead of snapping shut on a bang. From inside the house the two failures are easy to confuse.
If the issue is a cable, the fix runs through cable repair rather than spring work, and the price and parts involved are different. Either way the door should not be forced open or closed until someone has confirmed which part failed, since a crooked door under tension can bind or drop further.
What a homeowner can see without touching anything
Stand back and look at the spring above the door, usually a single long coil mounted on a shaft. A clean separation in the coil, a visible gap, or one half hanging loose is the clearest sign of a broken torsion spring. If instead the door sits crooked, with one corner lower than the other, a cable or drum issue is more likely the cause.
Either way, resist the urge to pull the emergency release cord to test it. The manual release cord disconnects the door from the opener carriage so the door can be moved by hand, which is only safe when the springs are intact. With a broken spring, pulling that cord can let a heavy door drop fast.
Older Daly City garages: check more than the spring
Housing stock matters here. In Daly City, 41.8% of homes were built before 1960 and the median year built is 1965, per the Census Bureau's ACS 2024 5-year estimates, with the 1950s the single decade holding the most homes still standing at 24.5%.
South San Francisco and San Bruno show a similar pattern, with 42.8% and 47% of homes respectively built before 1960, per the same ACS 2024 5-year estimates. Older construction does not by itself mean an older spring, since springs get replaced on their own schedule, but it does mean the opener hardware and track alignment are worth a full look whenever a spring lets go.
Do not test the opener or try to force the door
Once a bang has happened, leave the opener alone. Pressing the wall button or remote again can run the motor against a spring that is no longer doing its job, and that is how gears, belts, and circuit boards get damaged on top of the original break. The door staying shut is the safe outcome, not a problem to solve by brute force.
If the garage is the only way to secure a vehicle or access the house, that is a different kind of urgency, and it is worth looking at emergency repair options rather than improvising with ladders, clamps, or extra muscle. A door under broken spring tension is unpredictable, and that is exactly the kind of job to hand off rather than attempt solo.
The replacement job and what it involves
Spring replacement is a standard repair, not a rebuild of the whole door. A technician matches the new torsion spring to the door's weight and cycle rating, installs it under controlled tension with the right winding bars, and checks the cables and drums while everything is already open. Full details sit on the spring replacement page, including the starting price for the repair itself.
After the new spring goes in, the technician usually checks the door's balance by hand and resets the opener's travel limits if the old spring had been sagging for a while before it broke. That extra pass catches a second failure, a worn cable or a drum that slipped, before it turns into another bang down the line.
American Garage Door Solutions explains that a loud bang in a Daly City garage most often means the torsion spring broke, leaving the door too heavy to lift until it is replaced.
The likely fix
The usual repair is a matched torsion spring installed under controlled tension, sized to the door's weight and cycle rating. The technician typically checks the lift cables and drums at the same time since they share the same shaft and can reveal a second problem early.
Torsion spring replacement
A matched pair of springs on a standard double door, then the door is balanced and tested
What can raise the price
- Heavier springs for a wood or oversized door
- High-cycle springs
- A worn center bearing or drum
From $285
How we check it
- Looks for a visible gap or separation in the spring coil
- Tests cable tension and drum seating on both sides
- Checks opener force setting and travel limits after the repair
Questions
Can two torsion springs break at the same time?
It is uncommon but possible, especially if both springs are the same age and have carried the same load for years. A technician checks both during the visit so the second one is not left to fail soon after.
Will the opener be damaged if I already tried the remote after the bang?
Sometimes, since the motor can strain against a door with no spring support. The technician checks the drive mechanism and gears during the repair visit and flags any damage before closing the job.
Does a broken spring always make a loud bang?
Most torsion spring breaks do produce a sharp bang because the coil releases stored tension suddenly. A quieter failure is less common but the door becomes just as heavy and unsafe to lift.
Can I drive my car out if the door is stuck shut from a broken spring?
No, the door needs to stay closed until a technician arrives, since forcing it open by hand or opener risks the door dropping or the opener sustaining further damage.
How does the technician know if it's the spring or something else?
The technician inspects the spring coil for a visible break, checks cable tension at both drums, and tests opener force settings, confirming the cause before any part is replaced.