Garage Door Cable Snapped: What to Do

By some distance the most common reason a lift cable parts, and the location is nearly always the same: the lowest couple of feet, at or near the bottom bracket.

The logic is straightforward once you look at where that part of the cable spends its life. It sits at the base of the opening, an inch or two off the concrete, at the exact height where water collects, where a hose reaches, and where anything running down the driveway ends up. Galvanized cable resists that for a long time and not forever. Corrosion works into the gaps between strands where it's invisible, and the cross-section carrying the load quietly gets smaller.

Because it's chemical rather than mechanical, it doesn't announce itself as a change in how the door behaves. The door works exactly as normal right up until it doesn't.

And the important consequence: the other cable is standing in the same puddle. Whatever got to one has been getting to the other for the same number of years.

How you can tell: The parted end is dark and ragged rather than bright. Rust visible on the lower section of both cables. Often a garage that gets hosed out, or a driveway that drains toward the door.

Worth separating out, because fitting new cables into the same conditions gets the same result on the same schedule.

The sources we find most often aren't rain. An irrigation head aimed so it mists across the driveway apron. A driveway that slopes toward the garage rather than away, so anything that lands runs to the base of the door. A washing machine or water heater in the garage with a drain pan that overflows occasionally. Hosing out the garage floor, which is a perfectly reasonable thing to do and puts water exactly where the cable terminates.

Monsoon adds one more that people underestimate: a microburst doesn't drop water on a door, it drives it sideways at it. Water gets pushed under the bottom seal and up the inside of the jamb, which is precisely the zone we're talking about.

None of these are dramatic on their own. All of them are cumulative.

How you can tell: A water line, efflorescence, or rust staining on the concrete at the base of the opening. A sprinkler head within throwing distance of the driveway.

The mechanical version, and it shows up differently: broken strands standing out from the bundle partway along the cable's length, like whiskers, well before anything fails completely.

Something is scrubbing the wire on every cycle. The usual culprits are a burr or a worn edge in the drum's groove, a cable that isn't running quite straight because the drum or the bearing plate has shifted, a bottom bracket that's slightly out of line so the cable enters it at an angle, or a track that isn't plumb and pushes the cable against a bracket edge.

Abrasion is the most fixable of the failure modes on this page, because it leaves visible evidence for a long time and because the underlying misalignment is correctable. It's also the one that gets ignored longest, since a few broken strands don't change how the door feels at all.

How you can tell: Fine wire whiskers standing out from the cable partway along its length. Sometimes a bright polished patch on a drum or bracket where the rubbing happens.

This one has a history rather than a location. If a cable has previously come off its drum and wrapped over the top of itself, the wire was compressed hard against itself under load. That flattens strands, breaks some of them internally, and leaves damage that isn't obvious from a casual look.

Put that cable back on the drum and it works. It just has a weakened section that will find its limit at some point in the following months.

This is the main reason a cable that has been through an overwrap gets replaced rather than reused, and why cables are replaced in pairs — matching condition on both sides matters as much for cables as it does for springs. It's also a reason to be wary of a repair where a displaced cable simply went back on without being examined properly.

How you can tell: The door had a cable off the drum at some point in the recent past, and this one failed near where the overwrap was.

Cables are strong in steady tension and considerably less forgiving of sudden loads.

The scenarios are all versions of the same thing: the door is moving and something stops it abruptly while the drums keep pulling. A door running against a manual side lock that's still thrown. A door coming down onto a solid obstruction rather than something that gives. A door with a bound roller that catches mid-travel. In each case the load spikes far above what the cable normally sees, and if the wire had already lost some strands, that's the moment it finds out.

The double bind here is that a shock load can also take a cable off its drum instead of breaking it, which is why the two symptoms come from overlapping causes even though they're different failures. Sometimes you get both on the same event.

How you can tell: The failure happened during a specific incident somebody remembers — a bang, a jam, a door hitting something — rather than appearing overnight.

The unglamorous one. Cables are consumable, and almost nobody treats them that way.

Every cycle bends the wire around the drum and straightens it again. Strands work against each other, the galvanizing wears thin at the contact points, and over enough cycles the cable simply reaches the end of its useful life. On a door that gets used as a household's main entrance, that arrives sooner than the calendar suggests, for the same reason it does with springs.

The reason this catches people out is that there's no service interval anyone knows about. Springs have a reputation and a rating. Cables have neither, so original cables routinely stay on doors for two decades, quietly getting worse, until one of them ends the discussion.

How you can tell: Original hardware on an older door, no history of any cable work, and a failure with no obvious single cause.

The genuinely useful part of this page, and the one that costs nothing.

Cables fail progressively. Strands break one at a time, and a cable that's on its way out looks visibly wrong for months. That's a long warning window on a component whose failure mode is sudden and whose repair is straightforward when it's planned.

All this needs is a flashlight, a couple of minutes, and the discipline to look at both sides rather than one. It's a look-only exercise — nothing here involves touching a cable, and there's a specific reason for that.

How you can tell: You're looking for whiskers, rust, thinning, kinks and anything that makes one cable look different from the other.