Extension Spring Replacement: preparing for the visit

Open the door by hand and it drifts back down on its own, a little at first and then all at once. Nothing is broken that you can see, but the springs along the tracks look tired, rusty and slightly sagging.

Worth answering before the call

Does the opener still move the door, and does it sound strained? Is a car parked inside that will need to come out first? Does the door drop the last bit, or drift up on its own?

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 is the difference between extension springs and torsion springs?

They balance the door in different places. Extension springs are the two long coils that run beside the horizontal tracks and stretch as the door closes; they work through pulleys and cables. A torsion spring is wound on a shaft above the door opening and turns drums that wind the cables. The parts, the way tension is set and the service itself are different, so it helps to say which you have when you call.