Is it the spring or the cable that broke on my garage door?

Look at the shaft above the door first. A gap of two to four inches in the coiled spring means the spring broke. If the spring looks intact but a cable hangs loose, sits off its drum, or pools on the floor, the cable broke. A broken spring makes the door dead heavy. A broken cable usually leaves it crooked.

The 60-second check: what to look at, in order

Run this with the door closed, standing inside the garage, touching nothing. DASMA, the trade association for door manufacturers, sets out the same order in its damage-check guidance for homeowners: start inside, keep the door closed, and keep a flashlight handy. Springs hold enough stored energy to cause serious injury, so this is a looking job only.

Three places, in this order:

1. The shaft above the opening. Follow the horizontal steel bar across the top of the door frame. Is the spring wrapped around it broken into two pieces?
2. The cables down each side. Follow the thin steel cable from the bottom corner of the door up to the grooved wheel at each end of the shaft. Is either one slack, off the wheel, or lying on the floor?
3. How the door sits in the opening. Is it square, or is one corner lower than the other?

Almost every case resolves on the first or second look. The third confirms it.

Tell 1: the gap in the spring coil

A broken torsion spring shows a clean break with daylight through it. The spring is the tightly wound coil mounted on the shaft above the door. Under load its coils sit shoulder to shoulder with no space between them. When the wire fails, the stored tension releases instantly, the two halves spin apart on the shaft, and you are left looking at a coil in two pieces with a visible gap between them, usually a few inches wide.

That gap is the single most reliable spring tell, and it is the reason a flashlight matters. Garages are dim, springs are dark grey or black, and a two-inch gap in a seven-foot ceiling is easy to walk past.

Two things that are not a broken spring:

• Rust or a squeal. A dry, rusty spring is a spring near the end of its life, not a failed one. DASMA notes that rust reduces the effective area of the spring wire and creates pits where fatigue cracks accelerate, so a rusty spring is a warning, not a diagnosis.
• A spring that looks slightly loose. Torsion springs sit in slightly different positions depending on whether the door is open or closed. Judge the gap, not the tightness.

Tell 2: the cable at the drum and down the side

A broken lifting cable shows up at the ends of the shaft, not the middle. The cable is braided steel wire rope. It runs from a bracket at the bottom corner of the door, up the inside of the vertical track, and winds onto a grooved wheel called a cable drum at each end of the shaft.

Four cable tells, from most to least obvious:

• A cable on the floor or hanging in a loop. A snapped cable has nothing holding it. It drops.
• A cable off its drum. The wire has jumped out of the grooves and is bunched to one side of the wheel or wrapped over itself.
• Visible fraying. Look at the last few inches near the drum and near the bottom bracket. Individual strands standing proud of the braid mean the cable is failing even if it has not parted yet.
• A gap at one bottom corner. The door sits flush on the concrete on one side and lifts away on the other.

Cables are strong. DASMA publishes a whole standard covering minimum breaking strength for lifting cables on sectional doors. When one snaps, it is almost always because it was frayed, corroded, or riding wrong on the drum for a long time first.

Tell 3: how the door sits and how heavy it feels

Symmetry separates the two failures when the parts themselves are hard to see. A door hanging evenly but refusing to lift points at the spring. A door hanging crooked, with one corner dropped, points at the cable on that side.

The reason is mechanical. A torsion spring sits in the centre and feeds torque to both drums through one shaft, so when it breaks, both sides lose support at the same instant and the door stays square while getting extremely heavy. A cable carries only its own corner, so when it parts, that corner drops while the other stays put.

Weight follows the same logic. Wayne Dalton describes the pattern plainly in its own service guidance: a spring that has broken or lost tension cannot help the door open, so the door opens only partway, opens slowly, or moves only a couple of inches. With a broken cable the door often still feels liftable, because the spring is still doing its job, but it binds or racks in the track as it moves.

Do not use a lift test as your first step. If you already have your answer from the spring or the cable, you are done. Testing by hand is covered in the next-steps section below and carries real risk on a door that has lost half its support.

The exception: Wayne Dalton TorqueMaster springs you cannot see

The coil-gap test is impossible on a Wayne Dalton TorqueMaster door, because the spring is sealed inside the tube. Wayne Dalton's TorqueMaster and TorqueMaster Plus systems put the spring inside a hollow steel tube mounted above the opening instead of wrapping it around an open shaft. Wayne Dalton describes it as a fully enclosed spring system housed in a steel tube, with no visible springs and nothing hanging outside.

That is a safety advantage, since a spring that breaks stays contained. It is also why an owner can look straight at a snapped TorqueMaster spring, see a smooth unbroken tube, and conclude the spring is fine.

How to spot one in ten seconds: if the bar above your door is a smooth painted tube with no coil wrapped around it, you have a TorqueMaster and this page's first test does not apply to you. Read the TorqueMaster page instead. The tests that work there are cable tension at the drum and the behaviour of the end brackets, not the coil gap.

Extension springs: a different layout with a different tell

If there is no spring above the door at all, look along the horizontal tracks near the ceiling. Extension springs are long, stretched springs mounted parallel to the tracks on each side rather than on a shaft above the opening. They power the door by stretching instead of twisting.

Extension springs fail differently and are easier to read. A broken one is visibly parted, and it usually goes limp rather than staying stretched. Because each side has its own spring working independently, one failed spring lifts one side normally and leaves the other behind, which produces the same crooked door a snapped cable does.

That overlap causes a specific confusion worth naming. Extension spring systems carry two kinds of cable, and only one of them lifts the door:

• The lifting cable, which runs from the bottom corner of the door and does the work.
• The containment cable, sometimes called a safety cable, which threads through the middle of the spring itself. Its only job is to catch the spring if it snaps. DASMA requires it precisely because unrestrained extension springs become projectiles.

A containment cable hanging with a broken spring on it is a broken spring, not a broken cable. Check where the loose cable attaches before you decide.

Why the answer changes what happens next

The two failures are different jobs with different scope, and that is why the distinction is worth sixty seconds. Both are urgent, but not in the same way.

A broken spring means the door is no longer counterbalanced. All of its weight is now on the opener, the cables, and the drums. DASMA's inspection checklist is unambiguous here: if a spring is broken, do not operate the door until the spring is replaced. Forcing it with the opener can pull cables off drums, rack the door out of square, and bend a panel, converting a spring job into a spring, cable, and panel job. If your door has two springs and one broke, the second is the same age with the same cycle count, and it is standard practice to replace them as a pair so the balance is even and the second failure does not follow in a few months.

A broken cable means one corner of the door has lost its support. The spring is still loaded and still dangerous, but the door can now bind, jam partway, or drop at a corner. Some doors have a bottom fixture designed to slow or stop a door's descent if a cable breaks, but you cannot count on having one. Cable work is usually the smaller job: the cable is replaced in pairs, the drums are re-seated and re-timed so both sides wind evenly, and the door is rebalanced. The spring normally stays where it is.

The order matters too. A cable that snapped on its own is a cable job. A cable that came off the drum because a spring let go is a spring job with cable work attached. If you can see both problems at once, the spring is almost always the cause and the cable is the consequence.

Whichever one you found, stop operating the door and leave the hardware alone. DASMA's guidance for homeowners is that if a problem shows up during a visual inspection, the inspection stops there and a trained door technician handles it. These are heavy assemblies held by parts under extreme tension, and the diagnosis is the part you can safely do yourself.