Garage Door Cable & Drum Repair, St. Louis

What the cables actually do

On a torsion-spring door, a steel aircraft cable runs from the bottom bracket at each lower corner of the door up the side of the opening and wraps around a grooved cable drum mounted on the torsion shaft above the opening. As the springs unwind, the drums turn and wind the cable in, and that is what physically lifts the door. The springs supply the force; the cables and drums deliver it to the door.

Which means the two cables have to work as a matched pair, winding the same amount at the same rate. When one goes slack, breaks or jumps its drum groove, the door immediately loses lift on that side and drops — and now all the load is going through one corner, one set of rollers and one track.

Symptoms: what you’ll see and hear

• The door hangs at an angle. One corner is several inches lower than the other and the top of the door is no longer parallel with the header. The most recognizable sign of all.
• Loose, drooping cable. You can see slack coiling near the drum or hanging down the side of the opening while the door is closed.
• Cable off the drum. The cable has unwound from the grooves and is bunched beside the drum or wrapped over itself on the shaft. Sometimes it wraps around the shaft itself.
• Frayed strands. Cable is stranded steel. It fails progressively — a few strands pop and stick out like a wire whisker, then more. If you can snag a glove on the cable, that cable is on borrowed time. Check just above the bottom bracket and at the drum, where they fail most.
• Rust or a wide dark band on the cable near the bottom bracket, where water pools on the slab.
• A pop or a bang mid-cycle followed by the door lurching or binding.
• The door binds, scrapes the jamb, or the rollers on one side are riding hard against the track.

Why cables fail in St. Louis garages

Moisture and corrosion. The dominant cause here. Most St. Louis garages are unconditioned. Summer dew points sit in the seventies and the concrete slab sweats; in winter you park a car covered in road salt slush and it melts onto the floor within a foot of both bottom brackets. The lowest 18 inches of each cable lives in that environment permanently. Corrosion works from inside the strand outward, so a cable can look acceptable and still have lost a meaningful share of its cross-section. Detached, unheated garages in South City, Lemay, Overland and Ferguson are the worst offenders, but attached garages in Florissant and Arnold show the same pattern.

Worn or damaged drums. The grooves in a cast aluminum drum wear, and a set screw that has loosened lets the drum creep on the shaft. Once the groove profile is gone the cable no longer tracks cleanly and begins to overlap itself, which is exactly how a cable jumps.

The door hit something. A trash can, a bicycle, a stack of firewood, a car bumper. The door stops on the obstruction, the springs keep unwinding, and the cable goes slack and unspools off the drum in a second. This is the single most common way a cable comes off with no warning at all.

Springs out of balance. Fatigued springs make the door heavy, and the extra load runs straight through the cables. A door that’s already dragging is chewing through its cables faster than you think. Cables and springs are the same age, and if one is going the other is usually not far behind — which is why we inspect both together.

Misalignment. A bent track or a bottom bracket that has shifted changes the cable’s path and makes it rub. Anything that abrades a cable shortens its life dramatically.

Why you must not keep operating the door

This is the part homeowners underestimate. With one cable failed, the door is being lifted from a single corner. Every cycle after that does compounding damage:

• The door racks in the opening, and the rollers on the low side get forced against the track flange until the track bends or the roller stems shear.
• The section that’s carrying the twist starts to buckle — that’s how a $200 cable job becomes a panel replacement or a whole new door.
• The door can come out of the track entirely, which is a separate and more expensive repair.
• The good cable is now carrying more than its design load and is far more likely to fail too.
• The opener is fighting a bind, which is a common way people strip the drive gear.
• And bluntly: an unbalanced door supported on one corner can drop. Nobody should be standing under it, and no car should be parked under it.

What to do right now: stop using the opener. If the door is down, leave it down and park outside. Pull the emergency release only if you understand that the door is not counterbalanced properly and may move on its own. Don’t try to re-seat the cable yourself — the cable is only slack because the spring tension isn’t currently on it, and putting your hands near a drum on a shaft that still has wound spring energy in it is how people get badly hurt. Call us. Most St. Louis cable calls are same day, and if a car is trapped we run 24/7 emergency service.

Why we replace cables in pairs

The same reasoning as springs, and it’s not a sales line. Both cables were installed on the same day, have lifted the same door the same number of times, and have sat in the same humidity and the same salt melt for the same number of winters. If one has corroded through, the other has corroded to roughly the same degree — it simply hasn’t been the one to let go yet.

There’s a second, more technical reason: cables have to be set to equal length so the door hangs level and both drums wind identically. Mixing a brand-new cable with a stretched, work-hardened one guarantees uneven lift, which puts the door slightly out of square on every cycle and wears the track and rollers. A pair of cables is an inexpensive part. Two separate service calls, plus the collateral damage in between, is not.

What the repair involves

• Door secured and spring tension safely managed before anything is touched. Cable work happens on a shaft that still holds wound spring energy — it’s handled with winding bars and clamps, not by hand.
• Both cables removed and replaced with the correct length and diameter for your door’s height and weight. Typical residential doors use 1/8" galvanized aircraft cable; heavier insulated doubles often call for 5/32".
• Drums inspected for groove wear, cracking and set-screw damage, then re-seated square on the shaft and set to matched positions. Worn drums are replaced — running new cable on a chewed-up drum just destroys the new cable.
• Bottom brackets checked. These are under constant tension and they corrode too; a rusted-through bottom bracket is a real hazard.
• Cable tension equalized and the door leveled so the bottom seal meets the slab evenly across the full width.
• Full hand balance with the opener disconnected — the door should hold position at waist height without drifting.
• Springs, bearings, rollers and track inspected while the technician is already in the system, so you find out about a marginal part now rather than in six weeks.
• Opener reconnected, travel and force limits reset, safety reverse tested. Typical job time is 45 to 90 minutes.

What cable repair costs in St. Louis

Prices are typical St. Louis-area ranges as of 2026 and vary by door size, spring cycle rating, hardware condition and access. Your exact price is quoted in writing before any work begins. Same flat rate in every ZIP code — see our pricing page.

Cables are the classic example of why a yearly tune-up pays for itself: a technician spots a frayed strand in thirty seconds, and catching it early is the difference between a $180 repair and a cascading failure that takes out the track and a panel. We handle cable and drum work across the metro, including Webster Groves, Fenton, St. Charles and Kirkwood. If the door is already out of the rails, go to off-track repair; if it’s noisy as well as crooked, see roller and track repair.