

Springs · Toronto
Extension Spring Replacement
The door climbs with the left corner ahead of the right, then twists as it turns into the ceiling track.
In plain words
Every extension spring should carry a containment cable, and replacement is the moment to make sure yours do. A containment cable runs through the centre of the spring and is anchored at both ends, to the rear hanger and to the bracket at the front of the track. It does no lifting; its purpose is to hold a spring that breaks so the pieces stay on the cable. Many older doors predate this practice, which a home inspection checklist checks for. When springs are replaced, new containment cables are fitted with them, which keeps a broken spring's pieces contained, not the door's weight, balance or safety.
How the visit goesYou pulled the red cord to open the door during a power cut and it barely moved. Lifting it took your whole weight, and when you let go it came down hard. It used to float up with one hand.
Extension Spring Replacement
How the visit goes


Pulleys, cables and the hooks that set them
Each side of an extension system has two pulleys, one on the moving end of the spring and one fixed at the front of the horizontal track, and a lift cable that runs from the bottom bracket over both to an S-hook or clip on the track hanger. Each pulley is spun to feel for a rough bearing and looked at for a wheel worn to a sharp groove or wobbling on its bolt. The cables are followed for fraying, rust at the bottom loop and a wrap that has slipped off a pulley. Worn pulleys and cables are renewed with the springs, since a seized pulley is often what shortened the old spring's life.
Taking the old springs down
With the door open and clamped, each old spring is nearly slack, and removal is straightforward. The technician unhooks the lift cable from its S-hook or clip at the front, which lets the spring's pulley end drop free, then lifts the rear loop off the hanger. The old containment cable is unclipped from its anchors and pulled out of the coil. On a door with a broken spring, the two halves are gathered and the containment cable, if there was one, is inspected for the marks of having done its job. Everything that comes down is laid out on the floor so the old spring can be measured against its replacement and you can see the wear.
A monthly look along the springs
Extension springs are easy to inspect because they hang in plain view. Once a month, with the door fully closed so the springs are stretched, stand inside and look along each one from the back hanger to the pulley. The coils should be evenly spaced along the whole length; a section stretched wider than the rest is a spring losing its temper. Then raise the door and look again: with the door open the coils should close up tight, and both springs should hang at the same height. Rust bloom, a pulley that sits crooked, a cable off its groove or a containment cable hanging loose are all worth a call while they are still small.
Extension Spring Replacement
In the van
Replacement rollers and hinges
Bottom brackets and clevis pins
Pulleys (sheaves) and forks
Track clamps or locking pliers
Rear spring hangers and angle iron

Extension Spring Replacement
What affects the quote
Opener adjustment and testing
Resetting the opener's force and travel to the newly balanced door and running the reversal tests is a short task that the quote names when it applies.
Working room around the springs
Shelving, a stored canoe or a car parked under the tracks slows the work along the horizontal run. Clearing the sides of the garage beforehand keeps the time on the quote short.
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
- Does the door drop the last bit, or drift up on its own?
- Is a car parked inside that will need to come out first?
- Is there anything stored beside the tracks or under the springs?
Extension Spring Replacement: questions
QuestionsCould I switch to torsion springs instead of replacing the extension ones?
Sometimes, and it is worth asking. A torsion system needs room above the door opening for its shaft and a header that can carry the spring bracket, which many older garages with a low ceiling simply lack; extension springs are there for that reason. Where the headroom exists, a conversion is a separate job with its own hardware and quote. The technician can tell you on the spot which route suits your garage.
Do the pulleys need replacing at the same time?
Often, yes. Each side has two pulleys, one on the spring and one fixed at the front of the track, and the cable rides over both on every trip. A pulley whose wheel has worn a sharp groove, or whose bearing has stiffened, drags on the cable and adds load the spring has to overcome, which is a common reason the old spring wore early. Pulleys that spin freely and run true can stay.
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.
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