Extension Spring Replacement: preparing for the visit

The 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.

Worth answering before the call

Is there a thin cable running through the middle of each spring? Is it a single or a double door, and what is it made of? Does the door drop the last bit, or drift up on its own?

The door creeps open on its own. Is that a spring problem?

Usually, yes. A door that rises from the floor or from halfway without help has springs pulling harder than the door weighs, which happens when a heavier-rated pair was fitted, when the hooks were set with too much stretch, or when a door has been made lighter by a panel change. It also puts strain on the opener, which has to hold the door down. Weighing the door and fitting the correct rating, set evenly, settles it.

Do the pulleys need replacing at the same time?

Often, yes. Each side has two pulleys, one on the spring and one fixed at the front of the track, and the cable rides over both on every trip. A pulley whose wheel has worn a sharp groove, or whose bearing has stiffened, drags on the cable and adds load the spring has to overcome, which is a common reason the old spring wore early. Pulleys that spin freely and run true can stay.