Springs · London
Garage Door Cable Replacement
There was a sharp crack from the garage, and when you went to look the door had dropped on one side and jammed.
In plain words
Two steel cables do the lifting on a sectional garage door. Each runs from a bracket at a bottom corner up to the counterbalance, and the springs pull on the door through them. Cable replacement renews that link. The technician secures the door, takes the tension off the springs, removes the worn or displaced cables, fits new ones matched to the door's height and weight, and re-tensions everything so both corners rise together. The result is a door that travels level again, closes flush to the floor, and asks the opener for the modest effort it was designed to give.
How the visit goesStanding inside with the door closed, you notice the cable on the right side near the floor has gone fuzzy. A handful of broken wires stick out like a bottle brush and the steel underneath is brown.
Garage Door Cable Replacement
How the visit goes
Both cables, side by side
Both cables are examined even when only one has failed, because they are the same age and have made the same trips. The technician looks along each for broken wires, thinning near the bottom loop, rust bloom, kinks, and flattened spots where the cable has rubbed. The ends get particular attention: the swaged stop that seats in the drum and the loop or ferrule that rides on the bottom bracket pin. The two are compared for length as well, since a stretched or slipped cable shows as one corner of the door sitting higher. This comparison decides what is fitted and explains any crookedness you have noticed.
Winding the springs back on
The torsion springs are wound back up with the winding bars, a quarter turn at a time, to the number of turns the door height calls for, which is roughly one full turn for each foot of door plus a small allowance the technician judges from the balance test. The cone set screws are tightened to the shaft, the bars are removed, and the clamps come off. The cables are watched as the door is raised to make sure each wraps onto its drum in a single neat layer with no overlap and pays out cleanly on the way down. A quarter turn added or removed fine-tunes the balance.
Checking the balance yourself, safely
You can confirm the door is still balanced any time without touching a spring or cable. With the door closed, pull the opener's release cord so the trolley disconnects, then lift the door by its handle or a safe gripping point to about waist height and let go gently. A balanced door should not lift or fall far on its own; a little slow drift is normal, and what calls for a technician is rapid movement, a heavy feel, binding in the track, or a result outside the manufacturer's balance instructions, not drift alone. Reconnect the opener as the manual describes, usually by running it once. Doing this each season catches wear early and keeps the opener working lightly.
Garage Door Cable Replacement
In the van
Silicone garage-door lubricant
Track clamps or locking pliers
Bottom brackets with cable pin
Galvanized aircraft-type lift cables
Bottom rollers and hinges
Garage Door Cable Replacement
What affects the quote
Oversized, commercial or high-lift doors
Doors taller or wider than a standard residential opening, or fitted with high-lift hardware, use heavier cables and drums and take longer to set up, which the quote reflects.
Whether a matching part has to be special-ordered
Most drums, brackets and cable sizes are common stock, but an older or uncommon door sometimes needs a part matched to its exact dimensions. When that happens the technician identifies it on the first visit and arranges the part before the return trip.
Impact damage to track or sections
A bumper strike often bends the track, a hinge or the bottom section as well as displacing the cable. Straightening or replacing those parts is quoted as separate work.
What to have ready
- Is anything stored close to the door or under the spring shaft?
- Do you have the door's manual or a label showing the model?
- Does the opener still run, and does it strain or reverse?
Garage Door Cable Replacement: questions
QuestionsWhat are garage door cables made of?
They are galvanized aircraft-type wire rope: many fine steel wires twisted into strands, and the strands laid around a core, which gives a cable that bends around a small drum thousands of times without fatiguing. One end carries a swaged stop or a loop for the drum, the other a loop that fits over the bottom bracket pin. Diameter and length are chosen for the door's weight and height.
Is cable work different on a door with extension springs?
The idea is the same and the route is different. Instead of winding onto a drum, the cable runs from the bottom bracket up over a pulley at the front of the track, back over a pulley on the spring, and to an adjusting clip. The technician relaxes the springs by opening and clamping the door, replaces worn pulleys along with the cable, sets both clips the same, and confirms a containment cable runs through each spring.
What stops the door from falling if a cable lets go?
It depends, and not reliably. The other cable and its spring may hold that corner so the door tips and wedges in the track rather than falling square, and the rollers binding can add some resistance, but neither is dependable: the door can still drop unexpectedly on the failed side. Some doors also carry a broken-cable device on the bottom bracket that grips the track if a cable fails. Because the door may not be held at all, the technician clamps and supports it before doing anything else.
Related services
- Garage Door Hinge ReplacementPressing a hand against one of the middle hinges makes it rock on the panel.
- Garage Door Track Repair or ReplacementAfter a decade of slushy winters the bottom foot of the track is flaking rust.
- Torsion Spring ReplacementThe door drops the last stretch to the floor rather than settling, and when you stop it halfway by hand it slides down instead of staying put.