Torsion springs and winding bars can be bought online, and videos make the job look like an hour’s work, but the hazard lives in the energy a wound spring stores, which buying parts does not change. Wikipedia’s garage door article lists uncontrolled release of spring tension, and do-it-yourself repair without the right knowledge or tools, among the common causes of injury.
This guide sets out how those injuries happen and what changes when a technician handles garage door spring replacement. It ends with the steps a homeowner can take safely, which are short, useful and need no tools.
Where the danger in a spring job comes from
The danger is stored energy: a wound torsion spring holds enough torque to lift the entire door, and it releases that torque through whatever gives way first.
DASMA’s 2007 column on torsion springs calls the garage door typically the largest moving appliance in the home, and says its spring hazards are well known to door makers, the CPSC and the National Safety Council.
The manuals say it in capital letters. Clopay warns that springs and their hardware are under extreme tension and can cause severe injury or death if mishandled, and LiftMaster’s opener manual tells owners never to loosen or adjust springs, cables, pulleys or brackets. DASMA’s homeowner checklist reserves all spring repairs for trained door systems technicians.
How spring injuries happen
The sources describe a short list of ways a spring job goes wrong, and each ends with the spring’s force released through a tool, a bracket or a hand.
| What goes wrong | What follows | Where the warning comes from |
|---|---|---|
| A screwdriver or loose rod used in the winding cone | It slips or breaks under load and the spring unwinds through it | Clopay’s instructions; a spring supplier’s note on injuries |
| Set screws loosened with no bar seated in the cone | The cone spins free on the shaft | Clopay’s warning on reducing tension; a spring supplier’s measuring caution |
| A bottom bracket or red-headed bolt removed while the spring is wound | The bracket flies loose under the cable’s full pull | DASMA’s safety tips; Clopay’s manual |
| A loose center bearing plate or anchor pad | The springs can pull violently away from the wall | Clopay’s residential instructions |
| A spring wound backward or given too much torque | A safety issue for the installer and excess force on the hardware | DASMA’s sheet on cycle life |
| A spring dropped on concrete | Cracked cast cones that can fail during installation | DASMA’s sheet on cycle life |
| The wrong spring for the door | A door that drifts, jumps off the floor or may not reverse | DASMA’s sheet on cycle life; LiftMaster |
Bad luck is not on the list. Every row is a normal step done with the wrong tool or in the wrong order, which is why Clopay’s own FAQ says unwinding torsion springs takes specific tools and training and leaves springs off its list of owner repairs.
Winding bars against screwdrivers and other stand-ins
A torsion spring is wound and unwound with a pair of solid steel winding bars that fill the sockets of the winding cone, because anything thinner or weaker can slip, bend or snap under load.
DASMA’s glossary defines a winding rod as a solid rod that fits the socket of the winding plug. Clopay’s instructions ask for snug, constant-diameter bars of solid steel, pushed the full depth of the cone’s holes and held firmly by an installer standing to one side, and they rule out screwdrivers and every other substitute.
The reason is fit. A screwdriver shank rattles in a socket sized for a bar, so the spring can lever it out, and Clopay’s commercial manual cautions that any tool too large or too small may break. A spring supplier traces many injuries to screwdrivers used instead of bars.
Two bars are used so one always holds the spring while the other changes sockets. With one bar, or two that fit badly, there is a moment when only a hand holds a loaded cone.
The parts that hold a wound spring’s force
While a spring is wound, its force runs through the cone’s set screws, the center bearing plate and its anchor pad, the cables and the bottom brackets, and none of them can be loosened safely until the tension is gone.
Set screws lock the winding cone to the shaft. Loosened before a bar is seated, they let the cone spin; driven too far, they damage the tube. Clopay also says never to adjust the center bearing plate or red-headed fasteners once the springs are wound, since red marks a part that will be under extreme tension.
The anchor pad matters as much as the plate. Clopay calls for the wood pad above the door to be lagged into framing, never nailed, because a loose pad can let the springs tear away from the wall.
Bottom brackets connect to the springs through the lift cables. DASMA’s safety tips say they are under extreme tension and should be loosened only by a trained technician. The industry standard covering counterbalance hardware, ANSI/DASMA 103, protects them with fasteners that cannot come off by accident, fasteners needing special tools, or red fasteners with warning labels.
Why the second spring is part of the job
On a two-spring door, the spring that did not break is still fully wound, so any spring job begins by unloading a spring that has lost none of its force.
DASMA’s safety tips say to replace both springs even when only one has broken, since both have done the same cycles. Two springs do have an upside: if one breaks with the door open, a spring supplier notes, the other keeps the door from falling.
For a homeowner, the survivor is the trap. The broken spring looks like the problem, but the risky work is letting the tension off the one beside it, with bars, before anything else on the shaft is touched.
Kits, enclosed systems and extension springs
A kit, a winder system or a different spring type changes the parts in your hands, but not the force in the spring or the need to release it under control.
Kits can be chosen by color or door size, yet DASMA’s color code sheet says color identifies a spring only in part, so a kit picked by color can simply be the wrong spring.
Enclosed systems such as Wayne Dalton’s TorqueMaster and Clopay’s EZ-SET were designed to make installation safer. Even so, the TorqueMaster Plus instructions require the tension to come off before any hardware, since a sudden release can injure badly.
Extension springs store force by stretching, and DASMA notes they are under high tension whenever the door is down. Their cables, pulleys and hooks carry that load too, and the torsion versus extension guide sets both spring types side by side.
What a technician does differently
A technician works against the same physics with the right tools and a fixed order, so no step relies on a hand holding back a loaded spring.
- The door is pinned and the power cut. A clamp on the vertical track keeps the door from rising, and the opener is unplugged.
- The survivor comes down first. Its tension is released with two fitted bars, one seated in the cone at every moment.
- Readings are checked against the door. When spring and door disagree, DASMA describes weighing the door on a scale once its counterbalance is disabled.
- The bare shaft gets inspected. Cones, drums, cables, bearings and the anchor pad are looked over while nothing is loaded.
- The new springs follow the maker’s chart. Turns come from the door’s height and drums, with both springs wound alike.
- The result is proven. The door is balanced by hand, then run on the opener, which must reverse on an obstruction.
How a balanced door behaves
A balanced door rests wherever it is let go partway up, and DASMA’s homeowner checklist asks whether it stays put at 3 to 4 feet off the floor with the opener disconnected.
DASMA’s terms name the two ways it can be off. A door that tends to lift itself off the floor is hot off the floor, and one that will not stay fully open is dead in the head, which DASMA’s cycle life sheet ties to too little torque.
Try this check only on a door whose springs are whole, and only if the first few inches lift easily. With a broken spring it stops being a test, and our heavy door troubleshooting page covers that situation.
What a homeowner can safely do after a spring breaks
A homeowner’s share of a spring repair is everything that happens before tools come out: keeping the door shut, cutting its power, clearing the area and sending clear photos.
- Leave the door where it is. A door that is down stays down; do not lift it by hand or press the button, because the opener would be hauling the full weight.
- Unplug the opener. That stops a remote, a keypad or a family member from starting it out of habit.
- Keep people, pets and cars clear. Nobody walks beneath a door that has lost a spring, and a car parked inside waits for the repair.
- Leave the release cord alone on a door stuck partway open. DASMA’s checklist warns that a disengaged door can move unexpectedly; our guide to opening a door manually explains when the release is safe.
- Photograph instead of touching. Floor-level shots of the shaft, the gap, the cone and the cables let us bring the right springs; our measuring guide lists them.
- Keep hands off the hardware. Set screws, the center bracket, red-headed bolts and bottom brackets stay as they are until the tension has been released.
That list is short on purpose. Unwinding the survivor, swapping the springs and winding the new pair belong to a technician, and the short list done well makes the visit quick.