

Springs · Cannington
Extension Spring Replacement in Cannington
The opener groans on the way up and the door slams the last foot on the way down, hard enough to rattle the windows.
In plain words
What you have afterwards is a door that behaves like a much lighter object. Both corners leave the floor together, the door holds still when you stop it at waist height, and it settles onto the floor instead of slamming. The opener runs quietly, because it is guiding a balanced door rather than hauling a heavy one, and its safety reversing works as designed. Both springs are new, both carry a containment cable, the pulleys turn freely and both S-hooks sit in the same hole. You also get the spring rating and door weight written down, so the next set can be ordered without measuring everything again.
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.
Setting both sides to the same hole
The initial tension is set with the door open and clamped, so the technician is adjusting slack springs rather than loaded ones. Each cable's S-hook is placed in a hole on the hanger, or its clip set to a mark, and the two sides are put at the same position. The cables are drawn to the same snugness so that neither corner of the door is being pulled ahead of the other. A level across the top section confirms the door is square in its tracks. Only when both sides read the same do the clamps come off and the door come down for its first balance check.
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
Rear spring hangers and angle iron
Bottom brackets and clevis pins
Garage-door spray lubricant
Lift cables
Replacement rollers and hinges

Extension Spring Replacement
What affects the quote
Weight added since the door went in
Insulation panels, windows or a wood overlay fitted after the original springs mean a heavier rating than the old pair. The door is weighed and the quote reflects the door as it is now.
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.
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.
What to have ready
- Does one corner of the door hang lower than the other?
- Is the door closed, fully open, or stuck partway?
- Is there anything stored beside the tracks or under the springs?
Extension Spring Replacement: questions
QuestionsThe door creeps open on its own. Is that a spring problem?
Usually, yes. A door that rises from the floor or from halfway without help has springs pulling harder than the door weighs, which happens when a heavier-rated pair was fitted, when the hooks were set with too much stretch, or when a door has been made lighter by a panel change. It also puts strain on the opener, which has to hold the door down. Weighing the door and fitting the correct rating, set evenly, settles it.
Could 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.
Why does the door slam down the last bit?
A door that drops the final stretch is telling you the springs are no longer holding it. As an extension spring loses its temper it gives less pull near the bottom of travel, where the door needs the most support, so the door falls that last foot. Fresh springs matched to the door's weight bring the door down under control and take that shock off the bottom section and the opener.
Related services

- Garage Door Hinge ReplacementThe car nudged the door on the way in.
- 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 ReplacementSomeone left the snow shovel leaning in the opening and the door came down on it.