

Springs · Springwater
Extension Spring Replacement in Springwater
A bang like a dropped toolbox came from the garage last night.
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 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


Weighing the door
Extension springs are chosen by the weight they are built to lift, so the door is weighed rather than guessed at. With the opener released and the springs disconnected or slack, the technician lowers the door onto a scale set on the floor under the bottom section and reads the figure. That number, together with the door's height, sets the spring rating and stretch length. The old springs are measured as a cross-check, but the scale wins if the two disagree, because a door can gain weight from new panels, insulation or a cladding added since the springs went on.
Running the lift cables
Each lift cable starts at the bottom bracket, where its loop goes over the pin or is secured with a clevis pin. From there it runs up the vertical track, over the fixed pulley at the front of the horizontal track, back along the track to the pulley on the end of the spring, around it, and forward again to the S-hook or adjusting clip at the front hanger. The technician keeps the cable seated in each pulley groove and makes sure it passes on the correct side of the containment cable and the track. Cables are renewed if the old ones showed any fraying or rust, and always as a pair of the same length.
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
Lag screws and hanger bolts
Containment (safety) cables
Extension springs, matched pair
Replacement rollers and hinges
Track clamps or locking pliers

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.
How the door is sitting
A door resting closed with one spring gone is straightforward. A door stuck partway, twisted in its tracks or with a cable wrapped around a pulley has to be supported and straightened first.
Pulleys that need renewing
Each side has two pulleys, and a wheel worn to a groove or a bearing that has stiffened is replaced with the springs. The quote names how many and which type.
What to have ready
- Is a spring broken in two, hanging loose, or just looking stretched?
- Is there a thin cable running through the middle of each spring?
- Does the door drop the last bit, or drift up on its own?
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.
What is a safety cable, and does my door need one?
A safety or containment cable is threaded down the inside of each extension spring and fixed at the hanger behind and the bracket in front. It carries no load in normal use. If a spring snaps, the cable keeps the broken halves in place beside the track. Every extension-spring door should have one each side, and the industry's inspection checklist asks for it. Doors installed decades ago often have none; they are added with the new springs.
Would a stronger spring make the door easier to lift?
Not in a useful way. The aim is a spring that matches the door's weight, so the door holds still wherever you leave it. A spring rated above that weight pulls the door up on its own, makes it hard to close, and leans on the opener to hold it down. A spring rated below lets it sink. Matched springs, set to the same hook position, give the light, even feel you want.
Related services

- Garage Door Hinge ReplacementWatching from inside as the door opens, you can see the gap between the second and third panels open up on one side as they turn the corner into the ceiling, then close again.
- Garage Door Track Repair or ReplacementHalfway up, the door lurches and one roller rides onto the lip of the channel.
- Garage Door Cable ReplacementSomeone left the snow shovel leaning in the opening and the door came down on it.