You heard a bang from the garage, and now the door is sitting crooked, jammed, or hanging with one side lower than the other. There’s a good chance a lift cable has snapped. It’s a common failure, it’s fixable, and it’s one of the few garage door faults where the right response is to stop using the door immediately.
What the Cables Actually Do
The springs take the weight of the door. The cables transfer that lifting force from the springs down to the bottom corners of the door. On a typical sectional door there are two, one each side, running from a drum at the top down to a bracket at the bottom of the door.
Those cables carry the full weight of a door that can weigh 80 to 150 kilograms, under constant tension, thousands of cycles a year. When one lets go, the load transfers instantly to the other side — which is why a snapped cable makes the door go crooked rather than simply drop.
How to Tell It’s a Cable
Signs, in order of how clearly they point to a cable:
- The door is visibly crooked — one corner higher than the other, or wedged in the track at an angle. This is close to conclusive.
- A loose cable hanging — you can often see it dangling near the track or coiled at the drum.
- A loud bang, then the door jammed — the snap itself.
- The door drops faster than it should on the way down, or feels much heavier by hand.
- Frayed strands visible where the cable runs near the bottom bracket — this is the warning sign before it snaps.
If the door is level and simply won’t move, it’s more likely a spring or opener problem than a cable.
Why Cables Snap
Rust and corrosion. The most common cause in Sydney, especially anywhere near the coast. Salt air works into the strands from the bottom of the cable up, because that’s where moisture sits. In the Eastern Suburbs, Northern Beaches and Sutherland Shire we see cable corrosion years earlier than in western suburbs.
Fraying against a worn drum or pulley. As the drum groove wears, the cable no longer sits cleanly and starts chafing.
Bad winding. If a cable comes off its drum and gets re-wound incorrectly, it rides over itself and wears fast.
Age. Cables have a fatigue life like everything else. Around 10,000 cycles is typical — roughly 7 to 12 years for an average household.
Spring failure first. When a spring breaks, the sudden shock load often takes a cable with it. If both have gone, that’s why.
What to Do Right Now
Stop using the door. Don’t try the opener again “just to see”. With one cable gone, the door is being held by one side and the opener will make it worse — twisting the door in the tracks, bending sections, or pulling the second cable off its drum. A cable replacement is a modest job; a door that’s been forced with a broken cable can mean new panels and tracks.
Don’t try to lift it by hand. The weight is no longer balanced and it can come down hard and unpredictably.
If the door is up: leave it up and clamp both tracks just below the bottom rollers so it can’t drop. A pair of vice grips does the job.
If the door is down: leave it down. Your garage is secure. Park outside.
Don’t attempt this one yourself. Replacing a cable means releasing spring tension, and torsion springs store enough energy to break bones. This is genuinely one of the jobs to leave alone, regardless of how handy you are.
What the Repair Involves
A proper cable replacement is more than swapping the broken one:
- Secure the door and safely release spring tension.
- Replace both cables, not just the failed one. The other is the same age and has done the same work — replacing one is a false economy, and it’ll go within months.
- Inspect the drums for groove wear and the bottom brackets for damage.
- Check the springs. A cable that snapped from shock load often means the spring is at end of life too.
- Re-wind both drums evenly and re-tension so the door sits level.
- Balance-test: at waist height, released from the opener, the door should stay put.
Any technician who offers to replace just the one broken cable and leave the other is cutting corners.
How Long It Takes
A straightforward cable replacement on a standard sectional door is usually about an hour. If the door has been operated after the break and the tracks or panels are damaged, it takes longer and costs more — another reason to stop using it as soon as it happens.
Catching It Before It Snaps
Cables give warning if you look. Twice a year, with the door closed, look at the bottom half of each cable where it runs down to the bracket. You’re looking for:
- Rust or orange discolouration
- Broken strands sticking out — a “whisker” means the cable is failing
- Flattening or kinks
- Any slack when the door is closed — both cables should be taut
A cable showing broken strands should be replaced before it lets go. Catching it early means a planned visit rather than a jammed door and a car stuck inside.
This is part of what gets checked in an annual garage door service, along with spring tension, roller condition and door balance.
Getting It Sorted
We carry cables, drums and bottom brackets for all common door types, so most cable jobs are done in one visit. We’ll check the springs and balance at the same time — if the springs are near end of life, better to know now than to be back in three months.
Book a garage door cable repair or call 0468 688 145. Fixed-price quote before any work, and a 1-Year Labour Warranty on the repair.
If your car is locked in and you need it today, mention it when you call — cable jobs get priority because a door left in that state usually gets worse.
