A broken spring is the most serious and most misunderstood fault on a garage door, mostly because it looks like a simple mechanical problem. It is not. There is a large amount of stored energy in the spring, and the failure is usually accompanied by a door that is no longer held up.
Do this right now
- Stop using the opener. Do not run it up or down.
- Keep everyone clear of the opening, and keep cars back from it.
- If the door is open, do not try to push it closed by hand.
- If the door is closed and will not open, do not climb over or under it.
- If you can see a gap, a lean, or a spring that has separated, take a photo — it tells us the system and the size before we arrive.
What actually happened
A garage door is held up by counterbalance, not by the opener. The springs store the energy that offsets the weight of the door, and the cables transfer that to the door through the drums at the top of the tracks.
When a spring fails, that stored energy is released in a moment. A torsion spring, mounted horizontally above the door, whips across the ceiling. An extension spring, running along the ceiling to a bottom bracket, snaps back hard enough to strike the ceiling, walls, or anything in the way.
The important consequence is that the door is now held by something weaker. On a torsion door, a single failed spring can leave the door supported by the centre bearing plate and one remaining spring, which is a temporary condition rather than a safe one. On an extension-spring door, a broken spring or a snapped cable can mean the door has nothing holding it.
Why springs fail when they do
Springs fail from fatigue, and fatigue happens between cycles rather than during them. That is why a spring can break at midnight with no warning and no recent change in how the door behaves.
- Normal wear. Every cycle flexes the spring slightly. Over years that is enough.
- Corrosion. The single biggest accelerant. The paint on a spring exists to slow this down; once it is breached and rust starts, the section under the coating thins and weakens unseen.
- An under-rated spring. A cheap spring or one fitted to the wrong weight and height will be overloaded from day one. This is what happens after a bad DIY replacement.
- A door that is not balanced. Constant extra load on the springs shortens their life.
- Age. Extension springs generally have a shorter life than torsion, and a spring on a thirty-year-old door is at the end of its life whether or not it looks fine.
- Damage. A bent spring, a coil knocked by something in the ceiling, or a torsion tube that has been rotated or drilled.
Worth noting: on a torsion door, when one of the two springs fails, the other is usually not far behind. They were installed together and have done the same work.
Is it safe to open the door?
It depends on the system, and guessing is not worth it.
If you have a torsion system and the door is closed, it is often possible to open it manually, carefully, because the centre bearing plate and the remaining hardware are still holding it. It will be heavy. It should be lifted from the bottom rail and guided the full way, and you should not let it run.
If you have an extension-spring system, and particularly if a cable has snapped as well as a spring, the load path is compromised. That is not something to attempt without knowing the situation.
If the door is open, do not push it closed by hand. Support it or leave it and call.
If you cannot tell which system you have, call. A two-minute conversation about what you can see is better than a door coming down on you.
What the repair involves
Replacing a spring is not a single-part swap, and this is where doors get half-fixed.
- Identify the system and the size — torsion or extension, single or double, wire size and drum diameter, matched to the door weight and height.
- Check what failed with it — cables, drums, bottom brackets, and the centre bearing. A new spring pushing against a frayed cable is a safety problem on its own.
- Replace in matched pairs, with new cables and drums. One new spring on one old one is a repeat failure.
- Re-balance and force-test. Wound or tensioned to the correct setting, then verified through the full travel, and verified to hold the door’s weight with the opener disconnected.
If the door is an extension-spring door, converting to torsion is worth a conversation. It is the single biggest safety improvement available on an older door, and it removes the highest-consequence part of the system.
Related services & problems
These usually go together, because the same underlying wear shows up in more than one place.