Extension Spring Replacement: how the work is done

Extension springs are common on the detached garages behind older houses, where a low ceiling left no room for a torsion shaft, and those garages are rarely heated. Damp summers, hard frosts and salt carried in on the car pit the spring wire over the years, and a fatigued spring most often lets go on a cold morning when the steel is stiffest. Replacement fits a new pair rated for the door, renews the pulleys and cables that have rusted alongside them, adds containment cables where the original installation never had any, and leaves a door that lifts easily by hand when the power is out.

Hangers, brackets and what they are screwed into

Extension springs pull against whatever holds their back end, usually an angle-iron hanger bolted to the rear track support or lag-screwed into a ceiling joist. The technician checks that this anchor is tight, that the lag screws bite into wood rather than drywall or a split joist, and that the hanger has not bent under years of load. The bracket that carries the fixed pulley at the front of the track is checked the same way, along with the bottom brackets on the door that the lift cables pull on. An anchor that has loosened lets the spring's geometry drift, which is one reason a door slowly becomes uneven.

Running the lift cables

Each lift cable starts at the bottom bracket, where its loop goes over the pin or is secured with a clevis pin. From there it runs up the vertical track, over the fixed pulley at the front of the horizontal track, back along the track to the pulley on the end of the spring, around it, and forward again to the S-hook or adjusting clip at the front hanger. The technician keeps the cable seated in each pulley groove and makes sure it passes on the correct side of the containment cable and the track. Cables are renewed if the old ones showed any fraying or rust, and always as a pair of the same length.

Lubrication that keeps the new set turning

Twice a year, in spring and before winter, a can of garage-door lubricant does most of the maintenance the springs need. Spray a light coat along each extension spring, working from the hanger to the pulley; it slows rust in a damp garage and quiets the coils. Put a drop on each pulley axle and on the bolts through the pulley forks, then on the hinge pins and roller stems. Leave the tracks dry and wipe them clean, since grease there collects grit and stops rollers rolling. Heavy grease and general-purpose oil are avoided on the springs because they hold moisture against the wire. Run the door a few times afterwards to spread the film.