Garage door cable repair

Cables wear where they flex and rust where they stay damp. DASMA's safety tips tell homeowners to look at the cables where they attach to the bottom brackets on both sides of the door, because frayed or worn cables are in danger of breaking. The bottom corners take the most abuse: rainwater that migrates under the door, which DASMA calls a common occurrence, plus the constant flex as the cable feeds on and off the drum.

A cable that jumps its drum is usually a slack-cable problem. Cables stay in the drum grooves because the door's weight keeps them tight. If one side of the door hangs up in the track, lands on something, or gets knocked crooked, the cable on that side goes slack and can unwind off the drum. DASMA warns that cable slack and disengagement can lead to uncontrolled door movement, which is why its guidance on wall-mounted jackshaft openers puts so much weight on keeping cables taut.

A safe cable repair starts with the spring tension, not the cable. With the door secured, the torsion springs are unwound, the cables are replaced and seated in the drum grooves, the drum set screws are tightened, and the springs are wound back to the correct number of turns. It usually makes sense to replace both cables as a pair, because the side that didn't fail has the same age and exposure, and a matched pair keeps the door level.

We also look for what caused the failure. A drum with damaged grooves will chew up a new cable, a bent track or worn roller can make one side hang up again, and a badly rusted bottom bracket should be replaced, not reused. DASMA defines a cable safety device as a bottom fixture designed to slow or stop the door if a cable breaks; some doors have one, and if yours does, it gets checked too.

• Lift cables: fraying, kinks, rust and equal length side to side
• Cable drums: groove condition and tight set screws
• Bottom brackets: rust, bends and secure fasteners
• Track and rollers: anything that could make one side hang up

Salt and moisture are hard on cables, and Delaware has both. FEMA's coastal building guidance says metal corrosion is most pronounced within 3,000 feet of the ocean, and it notes that most jurisdictions require building hardware on coastal homes to be hot-dipped galvanized or stainless steel. On a garage near the beach, the place to look is where the cable meets the bottom bracket, the same spot DASMA tells homeowners to check, because rust and fraying there are easy to miss from across the garage.

Farm and shop doors in Kent and Sussex add size and duty. Bigger doors mean bigger springs and more load on each cable, and wall-mounted jackshaft openers, long used on commercial doors and now adapted for homes, free up the ceiling but depend on cable tension. DASMA's guidance for jackshaft openers on standard-lift track lists ways to keep cables taut: pitching the horizontal track, push-down springs, cable keepers and cable tension monitoring. If a cable keeps coming off, the fix may be in the setup, not the cable.