Why did my garage door cable come off the drum?

What's actually happening when a cable jumps the drum

Your garage door hangs on two steel cables. Each one winds around a grooved drum at the top corner of the door as the door opens.

Those drums sit on a shaft that a torsion spring turns. The spring does the heavy lifting. The cables just transfer that force to the door.

The system only works when both sides stay balanced. The moment one cable goes slack, even for half a second, it can slip out of its groove and off the drum.

So when you see a cable dangling and the door hanging crooked, the cable isn't the disease. It's the symptom. Something let that side lose tension.

That's why the fix is two parts: get the cable back on, and find out what caused the slack. Skip the second part and you'll be doing this again soon.

Why it happened, from most to least common

In the field, the number one cause is a spring problem. A torsion spring that broke or weakened stops holding the door evenly, and the lighter-loaded side sheds its cable.

Right behind that: the door hit something on the way down. A frozen threshold in January does this all the time. So does a trash can nobody moved.

Frayed cables are next. They wear at the bottom loop where they wrap the pin, and a loose, fraying cable wanders off track.

Less often it's the drum itself (a backed-out set screw or a crack) or a binding roller that racks the door. Both usually give warning noises first.

And sometimes it's simply a bad prior repair. Uneven drum winding from a rushed spring swap will shed a cable within days. If someone worked on your door last week, that's your prime suspect.

• Broken/weak torsion spring: door drops uneven, cable jumps
• Obstruction on close: one corner stops, other keeps going
• Frayed or stretched cable: loose cable leaves the groove
• Worn drum or loose set screw: cable loses its track
• Binding roller or bent track: door racks, cable slacks
• Uneven drums from a past repair: door runs cockeyed

What to do right now, step by step

First move: hands off the button. Every time someone tests the opener to see if it still works, they make it worse.

Unplug the opener so nobody triggers it. Then look up at the spring. A broken torsion spring has an obvious 2-inch gap in the coil, like someone cut a slice out.

If the spring is broken, you're done with the DIY path. Close the garage, keep people and pets out, and call a tech. The winding work is genuinely dangerous.

If the spring looks intact and the door is fully down, clear the floor. Move anything near the tracks. Check for ice or water at the bottom.

Now clamp a pair of locking pliers onto the track just below a roller on each side. This physically stops the door from dropping while you work.

Take photos of both cables, both drums, and the spring anchor. You want to see how the good side is wound so you can match it.

Compare the two cables. The slack one shows you which side lost tension. If that cable is frayed, don't just reseat it, plan to replace both.

Only reseat a cable if the door is secured, the springs are intact, and the cable is sound. Otherwise, this is a phone call.

2026 cost breakdown

If nothing broke and the cable just needs reseating, a pro visit runs $150–$500 in most US markets. That includes the service call, which is usually $75 to $125 on its own.

Cables themselves are cheap. A matched pair of standard 7-foot-door cables runs $15 to $40. The cost is the labor and the risk, not the part.

That covers cables, a couple of rollers, and hardware you might as well replace while you're in there.

If a torsion spring broke too, add roughly $150 to $300 per spring installed. Doors with two springs should get both replaced together, since the second is the same age.

Bent track adds $150 to $400 depending on how many sections. A cracked drum runs about $40 to $80 in parts plus labor.

The honest math: DIY saves you around $170 on the simple version. Whether that's worth handling loaded springs is a personal call, and for most people it isn't.

• Pro, cable reseat/replace only: $150–$500
• Professional repair typically runs $150–$500. This is not a DIY job, so plan on hiring a pro.
• Torsion spring add-on: $150 to $300 each installed
• Bent track repair: $150 to $400
• Cracked drum: $40 to $80 parts plus labor

DIY or call a pro?

Here's the clean line. If the springs are intact, the door is down and clamped, and the cable is undamaged, an experienced homeowner can reseat it.

If a spring is broken, if the cable is under tension, or if you don't own real winding bars, call a pro. No exceptions worth writing down.

The danger isn't the cable. It's the torsion spring six inches away, holding a few hundred pounds of stored energy. Rewinding it with the wrong tools is how people lose fingers.

A licensed garage door tech does this daily. They'll reseat the cable, rebalance the drums, and check the springs in under an hour.

If you're on the fence, get a phone quote. Many shops will tell you over the phone whether your description sounds like a simple reseat or a spring failure.

Can this wait?

No. This is an emergency-tier fix, and here's why.

With one cable off, the whole load rides on the other cable and the spring. That's not what they were designed for, and the second cable can let go next.

A door hanging crooked can also fall out of the track entirely. Nobody wants a 150-pound door coming down on a car hood or a kid.

Even if the door looks stable, don't park under it and don't let anyone walk beneath it. Secure the garage and deal with it same-day if you can.

The one thing worse than a cable off the drum is a cable off the drum that you ignored for a week.

Why winter makes this worse

Cold garages see more of these calls, and the physics is simple.

Steel springs lose a little tension when it's cold, so a door that was borderline balanced in summer runs uneven in a hard freeze.

Water under the door freezes overnight and glues the bottom seal to the concrete. Hit the opener and one corner sticks while the rest lifts.

That stuck-corner moment is a textbook cable-off-drum setup. The lifting side pulls, the stuck side slacks, and off it goes.

If you live somewhere with real winters, keep the threshold clear of standing water and break any ice seal by hand before running the door on freezing mornings.

How we put this together

This guidance comes from standard garage door service practice and the failure patterns techs see on residential torsion-spring systems.

Cost ranges reflect 2026 US pricing for typical single and double doors, including service-call fees where a pro is involved. Your local rates will vary.

We draw the DIY line conservatively on purpose. Cable work sits right next to loaded springs, and the injury data on spring work is not something to hand-wave.

When in doubt on your specific door, a phone consult with a local shop beats guessing. Describe the spring, the cable, and how the door is sitting, and most techs can triage it fast.