

Springs · Whitchurch-Stouffville
Extension Spring Replacement
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
Extension springs are the two long coil springs that run beside the horizontal tracks of a garage door, one on each side. They stretch as the door closes and pull back as it opens, and that pull is what makes a heavy door feel light. Replacement puts a new, matched pair on the door. The technician opens and secures the door so the springs are slack, removes the old set, fits springs rated for the door's actual weight with containment cables through their centres, threads the lift cables over the pulleys, and adjusts both sides until the door balances. The opener is reconnected and tested last.
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


Both springs, side by side
Even when only one spring has snapped, both are read closely. The technician looks for gaps opening between coils with the door up, which means the wire has stretched and lost its pull; rust pitting and scale, especially where the spring sits nearest the back wall; a spring hanging visibly longer or lower than its partner; and end loops that have opened or cracked. The two are compared for length, coil diameter and wire size, because springs of different ratings are sometimes found on the same door after a past repair. Whatever is found, the outcome is the same, a new matched pair, but the reading tells the technician what rating the door really needs.
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.
The numbers that stay with the door
Before leaving, the technician tells you what the door weighed, which spring rating and length went on, whether the pulleys and cables were renewed, and which hook position the cables were set to. Write it on a card by the opener or inside the door's manual. Extension springs are sold by rating and length, so the next set can be ordered from that card without weighing the door again, and a technician arriving later can see at a glance whether the door has been altered since. Add the date and roughly how many times a day the door is used; together those two facts give a fair idea of when the springs will be due again.
Extension Spring Replacement
In the van
Lag screws and hanger bolts
Track clamps or locking pliers
Pulleys (sheaves) and forks
Bottom brackets and clevis pins
Garage-door spray lubricant

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.
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.
Rollers, hinges and bottom brackets found worn
Cracked roller wheels, split hinges or a bottom bracket rusted at the cable pin are pointed out during the inspection and offered as optional items, since the door is already open and secured.
What to have ready
- Do the springs run along the tracks beside the door, or is there one spring above the opening?
- Is it a single or a double door, and what is it made of?
- Is there a thin cable running through the middle of each spring?
Extension Spring Replacement: questions
QuestionsWhy 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.
Only one spring broke. Why replace both?
The two springs are the same age and have stretched the same number of times, so the one still hanging is close behind. There is also a balance reason: a door lifts level only when both sides pull equally, and a new spring beside a worn one lifts its corner first and twists the door. Fitting a matched pair sets both sides the same and avoids a second visit a few months on.
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.
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 ReplacementAfter years of slushy winters the cables look thinner near the bottom brackets, with rust streaks running down the door where they attach.