How to Replace Garage Door Springs

Garage door springs fail predictably. When yours snaps—and it will, eventually—your door becomes a dead weight that won't open or close without serious effort. The springs are what actually lift the 300 to 400-pound door; the opener just guides it along the tracks. But here's the thing: these springs store enough energy to crush fingers, hands, or worse. A broken spring wrapped around a rod spinning at speed has killed people. This isn't scare-mongering; it's why most jurisdictions recommend hiring a licensed technician. That said, if you understand the danger, have the right tools, and follow the steps methodically, replacement is manageable. You'll need the exact spring type, a winding rod (not a substitute), and patience. Skipping steps or improvising will end badly.

1. Kill Power First. Unplug the opener from the electrical outlet completely. Do not rely on the remote or wall button. This prevents the door from being operated while you're working on it. If the door is currently up, manually prop it with a 2×4 under each side to hold it safely.
2. Match Specs Exactly. Look at the side of your existing spring(s). There's a label stamped or painted on the spring showing the length, wire gauge, and direction (left or right wind). Write this down exactly. Order replacement springs with identical specs—springs are not interchangeable. Take a photo of the label and bring it to a garage door supplier, or order online with the full part number. Do not guess on specifications.
3. Unwind With Precision. Locate the winding cone (the twisted part at the end of the spring). Insert a 1/4-inch winding rod into one of the holes in the cone. You need a real winding rod, not a screwdriver or drill bit—they slip and cause injury. Grip the rod firmly with both hands and carefully unwind the spring by rotating the rod counterclockwise. You'll feel resistance; take your time. Count the number of full turns as you unwind—you'll need this count to wind the new spring to the same tension. Once fully unwound, the rod should slide out easily.
4. Unbolt and Extract. Using an adjustable wrench or socket set, remove the bolts that hold the spring brackets to the header frame above the door. There are usually two brackets, one on each side. Keep these bolts in a cup or small container—you'll reuse them. Slide the old spring out of the brackets carefully. Set the old spring aside; don't throw it away until you've confirmed the new one works.
5. Mount With Alignment. Slide the new spring into the brackets, matching the left/right orientation of the old one exactly. The winding cone (the twisted end) should face the same direction as the old spring did. Reinstall the mounting bolts and tighten them firmly with the wrench, but don't strip them. Make sure both brackets are secure and the spring sits evenly in both bracket seats.
6. Wind to Target Tension. Insert the winding rod into the winding cone of the new spring. Turn the rod clockwise, counting each full rotation. Wind the spring to the same number of turns you counted when releasing the old spring. This is critical—too little tension and the door won't open; too much and you'll strain the opener. After each full rotation, pause and check your count. When you've reached the target turn count, remove the rod slowly and carefully.
7. Verify Full Operation. Remove the 2×4 props from under the door (if you used them). Manually lift the door from the closed position—it should rise smoothly and stay open at about waist height without slamming down. If it feels too heavy or too light, the tension is off and you'll need to adjust. Once the manual test passes, plug in the opener and test it with the remote or wall button. The door should move smoothly in both directions.
8. Confirm Durability. Springs settle slightly after the first few operations. Go back and visually inspect the brackets, bolts, and spring after a week of normal use. Tighten any bolts that have loosened. Listen for new squeaks or unusual noises, which may indicate misalignment. If everything looks and sounds normal, the job is complete.