Garage Door Cable Replacement: getting ready

There was a sharp crack from the garage, and when you went to look the door had dropped on one side and jammed. A length of cable lies coiled on the floor by the bottom roller.

Worth answering before the call

Do you have the door's manual or a label showing the model? Can you see a cable hanging loose, frayed, or wound around the shaft? Is it a single or a double door, and roughly how tall?

Why should the bottom brackets never be loosened by hand?

The bottom bracket is where the cable attaches, so whenever the springs are wound it carries a share of the door's weight as tension. Loosening it while the counterbalance is loaded releases that tension all at once. Many manufacturers now fit tamper-resistant fasteners for this reason. The technician unloads the springs first, after which the bracket is just a piece of hardware to unbolt and replace.

What makes a cable fray?

Fraying is individual wires breaking, and it comes from two things: bending fatigue where the cable wraps the drum or pulley, and rubbing where it touches something it should not, such as a bent track edge, a rough drum groove, a seized pulley or a bracket sitting crooked after a bump. Corrosion speeds both. The technician looks for the rough edge so the new cable does not meet it.