How do you replace garage door cable?

To replace garage door cable that is broken, frayed, or has fallen off drum, you need to safely release spring tension, remove old cable, install new cable, and restore tension, but this is high tension work best done by professional. First, close garage door completely and secure it with locking pliers or C-clamps on tracks just above rollers to prevent movement. For torsion spring system above door, you must use solid steel winding bars to carefully unwind torsion springs, counting quarter turns, typically 30 to 36 quarter turns for 7 foot door, to release tension; never use screwdrivers as they can slip and cause severe injury. Once tension released, loosen set screws on cable drums, remove old cable from drum and bottom corner bracket, and inspect drums for damage. Install new galvanized aircraft-grade cable of correct length for door height, threading it through bottom bracket and winding it correctly around drum in proper groove, ensuring it is not twisted and seats evenly. Rewind torsion springs to original tension and tighten set screws securely. For extension spring system, open door fully, clamp it, and disconnect extension springs and safety cables to relieve tension before swapping cables. Always replace both cables to ensure even lifting and balance. Wear safety glasses and gloves, and keep hands clear of springs. After replacement, manually lift door halfway to test balance; if door stays, tension correct. Professional replacement costs 100 to 250 dollars for cables alone, 250 to 600 dollars with springs, and includes warranty.