Garage Door Spring Repair & Replacement

How a torsion spring actually works

A torsion spring sits on a steel shaft above the door opening. As the door closes, the cables wind onto drums at each end of that shaft and twist the spring, storing energy. When you open the door, the spring unwinds and returns that energy, lifting the weight for you.

Balance is the whole point. On a correctly sprung door you can stop it at waist height with the motor disconnected and it will simply stay there — neither falling nor rising. That single test tells a technician more about a door's condition than any electronic diagnostic.

Torsion springs versus extension springs

Torsion springs are the modern standard on sectional doors: mounted centrally, wound under controlled tension, and safer in failure because the spring stays captive on its shaft.

Extension springs stretch along the horizontal tracks and are still found on tip-up doors and older installations. They do the same job less elegantly, and when one breaks it can travel — which is why safety containment cables through the centre of an extension spring are not a nice-to-have.

Both types are fitted and replaced. What we will not do is fit a torsion conversion to a door that does not have the headroom for it, or leave an extension spring without its containment cable.

Why garage door springs break

Springs fail from fatigue, not from abuse. Every open-and-close is one cycle, and a standard spring is rated at roughly 10,000 of them. A household opening the door four times a day reaches that in about seven years; one opening it ten times a day gets there in under three.

Three things accelerate it. Rust, which pits the steel and creates a stress point — the reason a light oiling once a year genuinely extends spring life. Incorrect sizing, where a spring that was never right for the door weight has been fighting from day one. And imbalance, where a worn partner spring, dragging rollers or a bent track make the surviving spring work harder than it was rated to.

Signs a spring is about to go

The failure is instant but the warning is not. A spring on its way out shows up first in how the door behaves, and it is worth acting at that stage rather than the next one.

• The door feels heavier by hand than it used to, or will not stay at waist height
• It opens more slowly, or the motor sounds like it is straining on the way up
• You can see a gap in the coil, or the spring has separated into two visible sections
• The coils look rusty, stretched, or unevenly spaced along the length
• The door judders or jerks upwards instead of moving in one smooth run
• It slams the last stretch on the way down instead of settling

What happens when a spring breaks

The door becomes its raw weight — commonly 80 to 140kg on a double sectional. An automated opener will strain, trip its overload and stop, or lift the door 100mm and give up. If the opener is strong enough to keep trying, it damages itself, the trolley, and eventually the top section of the door.

Manually, the door is now genuinely dangerous. A door part-way open on a broken spring is held by nothing but friction and the second spring, if there is one. It can come down fast and it does not stop for whatever is underneath it.

The right response is to stop. Leave the door closed if it is closed. If it is open, do not walk under it, do not put a car under it, and call for an emergency garage door call-out.

Why both springs get replaced together

On a dual-spring door, both springs were fitted on the same day and have done exactly the same number of cycles. When one fails, the other is not healthy — it is simply a few weeks behind.

Fitting one new spring against one aged spring also unbalances the door, because the two no longer pull with the same force. The door lifts skew, one cable takes more load than the other, and the rollers grind against the track on the loaded side. Replacing the pair costs marginally more once and avoids a second call-out, a second labour charge and a door that never quite ran right in between.

Springs are not repaired. A fatigued spring cannot be restored, and a broken one certainly cannot — the only question is what replaces it and at what rating.

Standard-cycle springs suit a typical household door used a few times a day. High-cycle springs cost more, last considerably longer, and are the right answer for complexes, families running two vehicles in and out several times daily, and any door on a short-term rental or business premises.

If the door itself is at the end of its life — rusted bottom sections, impact-twisted panels — putting new springs on it is money into a door that will be replaced within a year or two. In that case you will be quoted the springs and a garage door replacement side by side, and the choice is yours to make with both figures visible.

Springs are consumables, but their life varies enormously with how the rest of the door is looked after.

• A light spray of proper spring lubricant once a year prevents the surface rust that creates fatigue points
• Keep the rollers and hinges lubricated, so the springs are not fighting friction on every cycle
• Have the balance checked annually — an out-of-balance door wears its springs faster than a busy one
• Do not let a partner spring stay in service past its rated life just because it has not broken yet
• Fix a dragging track or a seized roller immediately rather than living with it

All of that is covered in an annual garage door maintenance visit, which for most households costs less than the difference between a planned spring replacement and an after-hours emergency one.