Most people describe it the same way: a bang from the garage, loud enough to be alarming, and then a door that simply will not lift. The opener strains, or hums, or lifts the door three inches and gives up.
Nine times out of ten that is a broken torsion spring, and you can confirm it yourself in about thirty seconds without touching anything dangerous.
The thirty-second check
Stand inside the garage, well clear of the door, and look at the steel shaft running horizontally above the opening. Wound around it is one spring, or two on a wider door.
A healthy spring is a continuous tight coil from end to end. A broken one has a clean gap in it, usually two or three inches wide, where the coil has separated and the two halves have unwound slightly away from each other. It is unmistakable once you know to look for it. If you see that gap, you have your answer and you can stop looking.
Two other confirmations, if the shaft is hard to see. With the opener disconnected, a door with an intact counterbalance lifts with roughly ten pounds of effort and holds itself near chest height. A door with a broken spring is enormously heavy and will not hold anywhere. And if the door lifts a few inches and stops, that is usually the opener reading a load beyond its force setting and refusing, which is the same underlying fault.
What to do next, and what not to do
The important instruction is this: unplug the opener.
With the spring gone, the motor is being asked to lift the entire weight of the door rather than guide an already balanced one. That is how a nylon drive gear strips and how a control board burns out, and it turns a spring job into a spring job plus an opener job. Every time somebody keeps pressing the button hoping it will catch, the bill goes up.
If the door is down, leave it down and use another entrance. If it is stuck part-way open, keep people and vehicles out from under it and treat it as urgent, because a door being held up by a failed counterbalance is being held up by friction.
Why it broke, and why the timing felt random
Springs are rated in cycles, not years. One cycle is one open and one close. Ten thousand cycles is the builder standard, which works out at roughly seven to twelve years for a household opening the door four or five times a day. Use the garage as your main entrance at six or eight cycles a day and the same spring is finished in four or five years.
It is a fatigue failure. Every cycle flexes the wire slightly, cracks propagate from the surface, and eventually a coil separates. That is why there is no warning noise, unlike almost every other part on the door: nothing rubs, nothing drags, and then it goes.
The Carlsbad factor
Here the rating on the label is optimistic, and the reason is corrosion rather than use. Fatigue cracks start at surface imperfections, and salt air creates surface imperfections. Chloride pits the wire, each pit concentrates stress in a spot the design assumed would be smooth, and the spring reaches the end of its fatigue life earlier than its cycle count implies.
There is a visual test you can run on the spring that did not break. New spring steel is smooth and evenly gray. A spring that has spent years in marine air goes matt, dull and faintly rough or speckled. That texture is the pitting, and on a door within a mile of the water it means both springs are further along than their age suggests.
Why both springs get replaced on a two-spring door
This looks like an upsell and is not, and the reasoning is worth understanding so you can judge it for yourself.
Both springs on a double door were fitted on the same day. They have taken the same cycle count. Near the coast they have had the same corrosion exposure. The one that has not broken is therefore not in better condition, it is simply next, and usually within months rather than years.
There is a second reason. Uneven tension across the shaft racks the door in its tracks, which grinds garage door rollers on the low side and wears the track. Doing the pair while the shaft is already de-tensioned costs a fraction of a second visit and keeps the load balanced.
What it should cost
A single torsion spring fitted is an estimated $215 to $425. A matched pair on a double door is an estimated $325 to $545. An extension spring pair on an older door is an estimated $185 to $325.
Those are ranges rather than prices because four measurements come off your own door and decide the correct part: wire gauge, inside coil diameter, relaxed length and wind direction, read against the weight of the door. Anybody quoting a fixed spring price sight unseen is guessing at the wire size or quoting the cheapest one they stock.
Two upgrades are worth asking about. A 20,000 or 25,000 cycle spring adds an estimated $70 to $140 and roughly doubles the interval. And on the coastal side, a properly galvanised spring resists the pitting that is actually cutting the life short.
The one job never to attempt
A wound torsion spring stores hundreds of foot-pounds of energy and it stays stored with the door flat on the slab. Releasing it needs two purpose-made winding bars and a controlled sequence. A bar that slips out of a winding cone travels fast enough to break bone, and the majority of serious homeowner injuries around garage doors happen at precisely this step.
Screwdrivers and offcuts of rebar are not winding bars. There is no version of broken spring replacement that is worth attempting to save a few hundred dollars, and that is true whether or not a video makes it look manageable.
Short version
- Look for a two or three inch gap in the coil above the opening. That is your diagnosis.
- Unplug the opener immediately and stop pressing the button.
- Leave the door where it is and use another door.
- Expect the pair to be replaced on a two-spring door, and understand why.
- Ask about cycle rating, and near the water ask about the galvanising.