Torsion Spring Replacement: how the work is done

The finished result is a door that behaves the way a good garage door should: it lifts by hand with light effort, stays where you leave it at mid-height, closes softly and lets the opener run with little strain. Reaching that point involves measuring the door, choosing a matched spring, winding it to the correct turns and testing the balance through the full travel. The technician then runs the opener's reversal test and lubricates the moving parts. You are left with a record of the spring installed, so future service starts from known specifications.

Reading the spring itself

The first measurements come from the spring that is already on the shaft. The technician measures wire thickness across a run of ten or twenty coils, the inside diameter of the coil, the overall length of the spring when relaxed, and the wind direction, which is read from how the coils lean. On a two-spring door each spring is checked separately, because a left-wound and a right-wound spring sit on either side of the centre bracket. Any tag or colour marking is noted too. These numbers narrow down what the door was built with, and together with the door's weight they point to the correct replacement.

Winding with control

Winding is where a spring takes on its working tension, and it is done with two solid steel bars sized to the holes in the winding cone. The technician stands to the side of the cone, inserts one bar, turns a quarter turn, inserts the second bar, and transfers the load from bar to bar so the spring is never held by less than a full bar. The number of quarter turns is counted against the door height and drum type. When the count is reached, the spring is stretched slightly toward the drum and the set screws are tightened to the shaft while the last bar still carries the load.

Using the manual release with confidence

A balanced door is also a door you can operate safely by hand when the power is out. Pull the red release cord with the door closed to free the trolley, then lift the door with both hands on the handle or the bottom section; it should rise smoothly and stay open at full height. To re-engage, pull the cord toward the door until the trolley clicks back onto the carriage, or simply run the opener, which reconnects on most models. Because the spring now carries the weight, this is light work, and it is the recommended way to get a vehicle out during an outage.