Garage door cable came off the drum? What to do right now

If a garage door cable came off the drum, stop using the door. Leave it where it is, unplug the opener, and keep people and cars out from under it. The cable is what lets the springs carry the door's weight, so with one side slack the door can drop, twist in its tracks or jam halfway. Getting the cable back on means taking the spring tension off first, which is a job for someone with winding bars and a plan, not a screwdriver.

This is a cold-weather question here. Colorado Springs had its first freeze of the season on October 16, two weeks later than the usual early-October date, and the first snow at the threshold is never far behind. The most common way a cable jumps off in winter is a door frozen to the slab while the opener tries to lift it. Below is how to tell what happened, what you can safely do, and how to keep it from happening again.

What the cable and drum actually do

Most doors in the Pikes Peak region hang on torsion springs mounted on a steel shaft above the opening. At each end of that shaft is a grooved drum, and a steel lift cable runs from each drum down to a bracket at the bottom corner of the door. When the door rises, the springs turn the shaft and the drums wind the cables up in their grooves. The springs do the lifting; the opener only guides the door.

That system only works while both cables stay tight. If one goes slack, even for a second, the turns of cable can lift out of the grooves and fall off the drum. When the cable takes load again it winds on wrong, or not at all, and that side of the door stops being held.

How to tell the cable came off

• The door hangs crooked. One side sits higher than the other, or there is a wedge-shaped gap at one bottom corner when it is closed.
• A cable is hanging loose beside the track instead of running tight from the drum to the bottom bracket.
• The cable is wound unevenly on the drum, stacked on itself or sitting outside the grooves, when you look up at the ends of the spring shaft.
• The door stopped partway and the opener strained, then reversed, or the rollers on one side climbed out of the track.

If you also heard a loud bang and one spring now has a visible gap in its coils, a broken spring came first and the cable went slack because of it. That is a broken garage door spring replacement, and the cables get reset as part of it.

Why cables come off, most common first

1. The door is frozen to the floor. Overnight the bottom seal freezes to the slab. In the morning the opener starts, the springs turn the drums, but the door does not move, or one side breaks free before the other. The cable on the stuck side goes slack and slips off. This is the one we see after every early-season freeze.
2. Something under one side. A drift of snow, a block of ice off a car, a trash can or a step stool. The door lands on it, the opener keeps driving down, and the cable on that side loosens.
3. One side binding in the track. A bent track, a broken roller or a loose hinge lets one side lag behind the other. Uneven travel means uneven cable tension.
4. The opener runs the door too high. If the up limit is set past where the springs run out of wind, the cables go slack at the top and can jump off as the door starts down.
5. A worn cable or damaged drum. Frayed strands, rust or a chipped drum groove lets the cable ride out of place under normal use.
6. A broken spring. Covered above. The cables lose their tension the moment the spring lets go.

What to do right now

1. Stop pressing the remote and the wall button. Every run with a slack cable bends the door, the track or the opener rail a little more.
2. Unplug the opener so nobody in the house or a car remote tries it again.
3. Leave the door where it is. If it is open or halfway, do not pull the red emergency release. With one cable off, that side may not be held by the springs, and releasing the opener can let the door drop or swing.
4. Keep people, pets and cars clear of the opening. If a car is trapped inside, call before you try to get it out.
5. Take a photo of each drum, the loose cable and both bottom corners. It helps whoever comes out bring the right parts the first time.

Two things not to do. Do not loosen or remove the bottom brackets where the cables attach to the door; on most doors they are under full spring tension and can fly off. And do not try to wind the cable back onto the drum by hand with the springs still wound. Re-seating a cable properly means locking the door down, unwinding the springs with winding bars, resetting both cables to equal length, rewinding, and then checking balance.

Can you fix it yourself?

Honestly, most people should not. The fix itself is not complicated, but every step of it happens next to a spring that is storing enough energy to lift a few hundred pounds of door. The fixes that are fine to do yourself are the preventive ones below, plus clearing whatever the door landed on. Anything that touches the springs, the drums, the shaft or the bottom brackets belongs with someone who does it every day. That is garage door cable repair, and it usually includes checking the rollers and tracks on the side that came loose, because the cable is rarely the only part that took the hit.

The Colorado Springs part

• Sunny days, frozen nights. A clear afternoon melts snow at the threshold, the water runs under the bottom seal, and it refreezes overnight. That freeze-thaw cycle is exactly what glues a door to the slab here, often on mornings when there is no snow on the ground at all.
• Wind-blown snow. Out toward Falcon, Peyton and the east side, wind piles snow against the door unevenly, so one corner lands on a drift and the other does not.
• Higher ground gets it first. Monument, Black Forest, Palmer Lake and Woodland Park sit higher than the city and usually see the first ice and snow sooner and more often.
• Many doors are original to the house. In older neighborhoods the cables and drums are often as old as the springs, and a cable that has rusted at the bottom bracket is the one that frays or slips first.

How to keep it from happening again

• On a frozen morning, check before you press. If the door does not start up smoothly, stop. Break the seal loose gently with a plastic putty knife, or wait until the sun warms the threshold. Never let the opener keep pulling.
• Keep the threshold clear. Shovel or sweep snow and ice away from the bottom of the door, both inside and out.
• Look at a worn bottom seal. A cracked, flattened seal holds water against the slab. See how to replace a garage door bottom seal.
• Watch the door go up once a month. Both sides should rise evenly, and both cables should stay tight and wound neatly in the drum grooves the whole way.
• Have the door balanced and inspected once a year. A garage door tune-up before winter catches frayed cables, worn drums and a door that has drifted out of balance.

The short version

If a garage door cable came off the drum, stop using the door, unplug the opener, leave the door where it is and keep everyone clear. The cable went slack, usually because the door was frozen to the floor, landed on something on one side, bound in the track, or lost a spring. Putting it back means releasing spring tension first, so it is not a safe do-it-yourself fix. Keeping the threshold clear and stopping the opener the moment a frozen door hesitates prevents most of these.

Frequently asked questions

Can I still open my garage door if a cable came off?

You should not. With one cable off, that side of the door is not properly held by the springs. Running the opener or lifting by hand can drop the door, bend the panels or pull it out of the tracks.

Why did my garage door cable come off when it was cold?

Most often the door was frozen to the floor. The springs and drums turned, the door did not move, and the cable on the stuck side went slack and slipped off the drum.

Is a cable off the drum the same as a broken cable?

No. A cable off the drum is usually intact and can be re-seated once the tension is off, if it is not kinked or frayed. A snapped or frayed cable has to be replaced, and both cables are normally replaced together so they match.

Did my spring break too?

Look at the spring above the door. If there is a clear gap in the coils, it broke. If the spring looks continuous, the cable likely came off for another reason, such as a frozen or blocked door.

Why is my garage door crooked after it closed on something?

Landing on an object lets the cable on that side go slack, and it can come off the drum. The next time the door moves, that side lags behind and the door goes crooked.