Springs · London
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
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
Torsion or extension, and which extension layout
The technician confirms the counterbalance type before choosing any part. Extension springs hang beside the horizontal tracks, one each side, with a pulley on the front end of each spring and a second, fixed pulley on the track angle near the door opening; the lift cable runs from the bottom corner over both. A torsion system has a spring on a shaft above the opening and belongs to a different service. Extension systems also vary: single or double springs per side on heavier doors, hangers fixed to the ceiling or to the rear track support, and cables that adjust at an S-hook, a clip or an eyebolt. Each affects the parts brought to the job.
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.
Checking the balance yourself
You can confirm the springs are still doing their share without going near them. With the door closed and nobody in the opening, pull the opener's red release cord so the trolley lets go of the door. Lift the door by its handle to roughly hip height and take your hands away. A door on good springs stays about where it is; if it sinks to the floor the springs have weakened, and if it rises on its own they are pulling harder than the door weighs. Either way it is a call rather than a job for you. Reconnect the opener the way your manual describes, usually by running it once.
Extension Spring Replacement
In the van
Door-weighing scale
Pulleys (sheaves) and forks
Garage-door spray lubricant
Lift cables
Bottom brackets and clevis pins
Extension Spring Replacement
What affects the quote
Converting to torsion instead
Where the garage has the headroom, some owners take the opportunity to move to a torsion system. That is a different job with different hardware and is quoted as its own option.
Track or section damage found on the way
A bent horizontal track, a bracket pulled off the jamb or a top section twisted by running the opener on a broken spring is separate repair work, quoted on its own.
Corroded fasteners
In an unheated garage the bolts through pulley forks and hanger brackets rust solid; freeing or cutting them and fitting new hardware takes time and shows in the parts list.
What to have ready
- Has insulation, glass or a wood facing been added to the door?
- Is the door closed, fully open, or stuck partway?
- Does the opener still move the door, and does it sound strained?
Extension Spring Replacement: questions
QuestionsI added insulation and windows to the door. Does that affect the springs?
Yes, and it is one of the more common reasons a pair of springs is suddenly found wanting. Insulation panels, glazed sections, a wood overlay or a new steel skin all add weight the original springs were never chosen for, so the door grows heavy and the opener strains. When the springs are replaced, the door is weighed as it is now, and the new pair is rated for the door you actually have.
What are the early signs that the springs are wearing out?
The door starts to feel heavier when lifted by hand and the opener sounds as though it is working harder. Released from the opener, the door sinks from halfway instead of holding. With the door open, gaps show between coils that used to sit tight together, or one spring hangs longer than the other. Rust bloom on the coils and a squeal from a pulley round out the list. Any of these is a good time to call.
Can I use the door as soon as the work is done?
Yes. The last steps of the visit are the balance test by hand, several full cycles under power and the opener's reversal checks, so the door is ready for normal use when the technician leaves. New springs need no settling period. It is worth running it yourself once or twice while the technician is still there, so you know what a properly balanced door sounds and feels like from now on.
Related services
- Garage Door Hinge ReplacementPressing a hand against one of the middle hinges makes it rock on the panel.
- Garage Door Track Repair or ReplacementAfter a decade of slushy winters the bottom foot of the track is flaking rust.
- Garage Door Cable ReplacementThere was a sharp crack from the garage, and when you went to look the door had dropped on one side and jammed.