It's not often that garage door cables break, but when they do, they can prevent your garage door from opening and closing properly, potentially leaving you stranded in your own garage. Fortunately, it doesn't take much to replace a garage door cable that's failed due to continuous wear and tear. You can use the following steps to help get your garage door back on track.
Before you can begin replacing your broken garage door cable, you'll need to relieve tension from the garage door springs. Start by opening the garage door fully. You may need to pull the emergency release handle to disengage the garage door opener trolley in order to open the door manually. Once the door is open, attach a couple of C-clamps or vise grips on the track just below the bottom roller.
Now you can focus on unwinding the garage door spring. Insert a winding bar into one of the slots on the spring's winding cone. Keep a firm grasp on the winding bar as you loosen the set screws on the winding cone, as this will transfer all of the spring's tension to the winding bar. Insert a second winding bar into one of the other slots on the winding cone.
Carefully unwind the spring by moving the winding bars downwards in quarter-turn increments. Make a mental note of how many turns it takes to unwind the springs, as this will be the number of turns you'll need to rewind the spring afterwards. Always keep one winding bar in the winding cone at all times and keep a firm grip on the winding bar.
Replacing the Broken Garage Door Cable
Once the garage door spring is fully unwound, loosen the set screw located on the cable drum at the end of the spring shaft. Once the drum is loose, carefully unwind the cable from the drum and unhook the remainder of the broken cable from the jamb bracket located at the bottom of the garage door. For safety's sake, you should wear thick gloves to avoid puncturing your hands on frayed or rusted sections of cable.
Once you have the new cable ready, locate the insertion slot on the cable drum and insert the squared-off end of the cable into the slot. Wind the cable around the drum, making sure it's approximately the same length as the old cable. Take the looped end of the new cable and attach it to the jamb bracket. After making sure there's little to no slack in the cables, tighten the set screws on the cable drum and make sure the drum does not spin independently of the spring shaft.
With the new cable in place, you can rewind the garage door spring to its original tension. Reinsert the winding bars and move them upwards to tighten the spring. Make sure you tighten the spring using the same number of turns as it took to loosen them. In most cases, it takes 30 quarter turns to tighten the springs.
Once you've tightened the garage door spring to its proper tension, tighten the set screw on the winding cone. This should be done while you have a firm grip on the winding bar, otherwise the spring could unwind suddenly and cause serious injuries to you and others nearby.
After securing the spring by tightening the set screw, carefully remove the C-clamps or vise grips holding the garage door open. At this point, you'll want to take note of how the garage door closes. If the garage door fails to close properly, you may need to adjust the door's balance. Once the door is properly balanced, reconnect the garage door opener trolley to the rest of the garage door. Replacing cables and springs for garage doors can be dangerous, so if this isn't a process you're comfortable doing on your own, reach out to a company like Jayton Door Corporation.