

Springs · Humber Summit
Extension Spring Replacement in Humber Summit
One of the springs beside the track is hanging loose at the front end, its pulley dangling, and a length of cable lies slack along the top of the door.
In plain words
Garage doors are balanced by one of two spring systems, and the extension kind is the one you find on many single-car doors and older detached garages. Instead of a spring wound on a shaft above the opening, an extension system uses two springs stretched along the horizontal tracks, working through pulleys and cables. It needs less headroom, which is why it suits garages with a low ceiling. Replacing these springs is its own service with its own parts: springs chosen by door weight, pulleys, S-hooks and containment cables. A technician confirms which system is on your door before any part is chosen.
How the visit goesThe opener groans on the way up and the door slams the last foot on the way down, hard enough to rattle the windows. The motor is the same one it always was; something in the springs has stopped doing its share.
Extension Spring Replacement
How the visit goes


Securing the door with the springs slack
An extension spring is stretched tight when the door is closed and nearly relaxed when the door is fully open, so the first move is to get the door up. The technician pulls the opener's release, raises the door by hand if it will go, and clamps both vertical tracks below the bottom rollers so the door cannot come down. If a broken spring has left the door stuck partway, it is lifted and supported with the weight taken on clamps and props before anything else is handled. With the door held open, the springs, pulleys and hooks can be examined and removed like ordinary hardware, which is the whole reason the sequence begins this way.
Balancing the door by hand
Balance is judged with the opener still disconnected. The technician lowers the door to the floor, then lifts it: it should rise with modest effort, stay put when let go at about waist height, sit steady when fully open, and come down under control rather than dropping. If it sinks, both springs need a little more stretch and each S-hook is moved one hole to take up cable; if it climbs on its own, one hole the other way. Adjustments are always made in pairs, with the door open and clamped again each time, so the two springs stay equal. Two or three rounds usually settle it.
Knowing when the next set is due
A standard extension spring is made for a set number of open-and-close cycles, commonly in the ten-thousand range, which on a door used four times a day works out to several years and on a door used twice a week to much longer. Springs age even when idle, as rust does its slow work in an unheated garage. The signs that the set is nearing the end are gradual: the door feels heavier by hand, the opener sounds as if it is working, the door drifts down from halfway, and gaps appear between coils when the door is open. Acting on those signs turns the next replacement into a planned appointment rather than a bang in the night.
Extension Spring Replacement
In the van
Extension springs, matched pair
Rear spring hangers and angle iron
Door-weighing scale
Pulleys (sheaves) and forks
Bottom brackets and clevis pins

Extension Spring Replacement
What affects the quote
Getting the van to the garage
A detached garage down a shared laneway, a rural property or a building with the bay behind a gate takes more time to reach and set up in, and the quote allows for that.
Door weight and size
Spring rating follows the door's weight, and a wide insulated door or a wood door takes heavier springs than a light single. Weight and height together set the parts on the quote.
Hangers and anchor points
A rear hanger that has loosened, a front bracket bent by a jumped cable, or framing that needs a new anchor point adds fasteners, angle iron and a little time.
What to have ready
- Is there anything stored beside the tracks or under the springs?
- Is there a thin cable running through the middle of each spring?
- Has insulation, glass or a wood facing been added to the door?
Extension Spring Replacement: questions
QuestionsHow do you know which springs my door needs?
By weight. Extension springs are rated for the weight they lift, so the technician releases the opener and weighs the door on a scale, then matches that figure and the door's height to a spring rating and stretch length. The old springs are measured as a check on wire size, coil diameter and length. Where the two disagree, the scale decides, since doors gain weight from added insulation or panels.
Should I try to open the door by hand before the technician arrives?
No need, and it is easier on the door if you leave it. With a spring broken or slack, the door is unbalanced and heavy, and lifting it can let it drop or twist a section in the track. If the door is stuck partway, leave it there and keep people and the car away from the opening. The technician brings clamps and props, and the door is secured before it is moved at all.
How long do extension springs last?
Springs are rated in cycles, one cycle being a full open and close, and a standard set is built for a number in the ten-thousand range. A door used four times a day gets through that in several years; a door used a few times a week takes far longer. An unheated, damp garage shortens the figure through rust. Regular lubrication and a door kept in balance stretch it out.
Related services

- Garage Door Hinge ReplacementOn the old wood door, one hinge has pulled away from the panel, dragging a screw and a chunk of soft timber with it.
- Garage Door Track Repair or ReplacementAfter a decade of slushy winters the bottom foot of the track is flaking rust.
- Garage Door Cable ReplacementThe cable has wrapped itself around the shaft above the door instead of sitting on its drum.