

Springs · Dorset Park
Extension Spring Replacement in Dorset Park
Open the door by hand and it drifts back down on its own, a little at first and then all at once.
In plain words
Extension springs are the two long coil springs that run beside the horizontal tracks of a garage door, one on each side. They stretch as the door closes and pull back as it opens, and that pull is what makes a heavy door feel light. Replacement puts a new, matched pair on the door. The technician opens and secures the door so the springs are slack, removes the old set, fits springs rated for the door's actual weight with containment cables through their centres, threads the lift cables over the pulleys, and adjusts both sides until the door balances. The opener is reconnected and tested last.
How the visit goesOpen the door by hand and it drifts back down on its own, a little at first and then all at once. Nothing is broken that you can see, but the springs along the tracks look tired, rusty and slightly sagging.
Extension Spring Replacement
How the visit goes


Both springs, side by side
Even when only one spring has snapped, both are read closely. The technician looks for gaps opening between coils with the door up, which means the wire has stretched and lost its pull; rust pitting and scale, especially where the spring sits nearest the back wall; a spring hanging visibly longer or lower than its partner; and end loops that have opened or cracked. The two are compared for length, coil diameter and wire size, because springs of different ratings are sometimes found on the same door after a past repair. Whatever is found, the outcome is the same, a new matched pair, but the reading tells the technician what rating the door really needs.
Fitting a pair that matches the door
The new springs are selected from the door's measured weight and its height, which together give the rating and the stretched length required, and they are fitted as a pair even if one old spring looked sound. The technician checks each new spring's wire size, coil diameter and relaxed length against the specification before it goes up, and confirms the end loops suit the hanger and the pulley fork. The rear loop is hung on the hanger and the front loop takes the pulley fork. On heavier doors that carry two springs per side, all four are renewed together. Nothing is hooked to the door yet; the springs simply hang in place, slack, waiting for the cables.
Lubrication that keeps the new set turning
Twice a year, in spring and before winter, a can of garage-door lubricant does most of the maintenance the springs need. Spray a light coat along each extension spring, working from the hanger to the pulley; it slows rust in a damp garage and quiets the coils. Put a drop on each pulley axle and on the bolts through the pulley forks, then on the hinge pins and roller stems. Leave the tracks dry and wipe them clean, since grease there collects grit and stops rollers rolling. Heavy grease and general-purpose oil are avoided on the springs because they hold moisture against the wire. Run the door a few times afterwards to spread the film.
Extension Spring Replacement
In the van
Track clamps or locking pliers
Extension springs, matched pair
Containment (safety) cables
Pulleys (sheaves) and forks
Replacement rollers and hinges

Extension Spring Replacement
What affects the quote
Rollers, hinges and bottom brackets found worn
Cracked roller wheels, split hinges or a bottom bracket rusted at the cable pin are pointed out during the inspection and offered as optional items, since the door is already open and secured.
Containment cables to add
A door that never had containment cables gets them with the new springs, along with anchor hardware into the framing. It is a small parts line and a worthwhile one.
Condition of the lift cables
Cables with fraying, rust at the loop or a kink are renewed as a pair while the springs are off. Sound cables are re-routed and set, and the quote says which applies.
What to have ready
- Has insulation, glass or a wood facing been added to the door?
- Does the opener still move the door, and does it sound strained?
- Is it a single or a double door, and what is it made of?
Extension Spring Replacement: questions
QuestionsWhat does the paint colour on the end of the spring mean?
Manufacturers dab a colour on the end coil to indicate the spring's weight rating, which is a handy starting point. It is not the final word: a faded or repainted end coil tells you little, and the pair on an older door may have been a near match rather than the right one. The technician treats the colour as a hint and confirms the rating from the door's measured weight and the spring's own dimensions.
What happens during the visit?
The technician releases the opener, opens the door fully and clamps it so the springs go slack, then inspects springs, pulleys, cables, hangers and containment cables and weighs the door. The old springs come off, a matched pair goes on with containment cables through them, the lift cables are routed over the pulleys and the two sides are set to matching hook positions. The door is balanced by hand, the opener reconnected and its reversing tested with you watching.
What information helps when I call?
Whether the springs run along the tracks or sit above the door; whether one is broken, hanging loose or just looks stretched; whether the door is closed, open or stuck partway and level or crooked; roughly how wide and tall the door is and what it is made of; and whether there is a cable running through each spring. A photo taken from inside with the door closed answers most of that at once.
Related services

- Garage Door Hinge ReplacementThe roller at the top of the second panel is leaning outward and only half of the wheel is still in the track.
- Garage Door Track Repair or ReplacementThe door has started rubbing the frame on the left, leaving a shiny stripe down the weatherstrip.
- Garage Door Cable ReplacementThe cable has wrapped itself around the shaft above the door instead of sitting on its drum.