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Replacing a Garage Door Spring

There are two basic types of garage door springs—extension and torsion. Here’s how to identify and replace them.

Inside of a garage looking out. Nat Rea

Garage doors are one of those things that you probably don’t think about. They go up and they go down. But after opening and closing them every day for six or seven years, the springs that help to support the weight of the garage door lose their strength or even break. Then what?

You could call a professional and spend a couple hundred dollars for the repair, in addition to the replacement parts. Or you could do it yourself. If you decide to go that route, you’ll first need to know that there are two types of garage door springs—extension and torsion.

Types of Garage Door Springs

Extension springs

Extension springs are located just above the door tracks that parallel the ceiling, perpendicular to the doors. At one end, they are attached to the rear track hanger; at the other, they attach to one or two pulleys that keep tension on the cables that raise and lower the door. There also should be a second set of safety cables that run through the center of the springs to keep them in place if the springs happen to break.

Extension springs function by stretching, thereby keeping tension on the pulley and cables. The pulling weight of extension springs ranges from 50 to 440 pounds. They are also categorized as to their length, typically expressed in inches that equal half the height of the garage door. This type of spring is expected to last for about 10,000 cycles (one opening and closing equals a cycle); you can also buy extension springs with an extended life of up to 20,000 cycles.

Torsion springs

Torsion springs sit above and parallel to the doors. They are mounted in pairs onto a horizontal shaft that’s connected to a cable drum at either end; brackets at each end support the shaft, and a center bracket separates the pair of springs. Instead of stretching, torsion springs work by tension.

They are installed under tension—wound up tightly on the shaft. When the garage door opens, the tension is gradually released, and the spring is unwound. When the door is closed, the springs are put back into tension again. Torsion springs generally have a longer service life than extension springs, averaging 15,000 to 20,000 cycles.

Both types of springs are color-coded with a touch of paint at either end to indicate their pulling strength and their length, which should be matched to the weight and height of the garage door.

How to Replace an Extension Spring on a Garage Door

When a spring breaks or has lost its tension, it must be replaced, and while you’re at it, you might as well replace its partner spring on the other side of the door.

  1. Look for a spot of paint at the ends of the old springs—it will help you determine the type of replacement to buy. (Search online for DIY garage door parts or check your local big box store.) If you can’t see any color, you’ll need to measure the door height in inches and divide by half; that will give you the correct length of the spring.
  2. Now estimate the weight of the door. The best way to do this is with an analog bathroom scale. With the door fully lowered, detach the garage door opener and the springs from the door. Lift the door enough to slide the scale underneath, then lower it and read the scale. The new springs that you choose should correspond to the height and weight of the door. This is a good time to evaluate the other parts of the system and replace frayed cables or worn/rusted pulleys at the same time.
  3. When you’re ready to replace the springs, park the car out in the driveway and gather your tools. You’ll need two C-clamps, an adjustable wrench and/or the correct sized box wrenches, a stepladder, and work gloves. First, raise the door until it’s fully in the up position. Tighten a C-clamp onto each side of the upper portion of the vertical door track to prevent the door from accidentally coming back down. It’s also good to unplug the garage door opener and disconnect it from the door.
  4. Now, unbolt the far end of the spring from the rear track stanchion, then unbolt the pulley and disconnect the cable. Disconnect the safety cable, slide it out from the inside of the spring, and remove the spring. Don’t dismantle the opposite side yet—you can use it as a guide to install the new spring.
  5. Connect the far end of the new spring to the stanchion. Thread the safety cable through the spring and attach it to the stanchion. Attach the free end of the spring to the pulley, and reattach the cable to the door. Repeat the process on the other side of the door, then reconnect the door to the door opener and plug it in.

How to Replace a Torsion Spring on a Garage Door

Torsion spring replacement is technically more difficult than that of extension springs and can be dangerous. If you’re not confident in your abilities, call a professional.

Torsion spring on a garage door Erin Little
  1. First, close the garage door and disconnect it from the garage door opener. Assuming that one of the two springs are broken, you’ll need to relieve the tension on the intact spring before replacing the broken spring.
  2. Set up the ladder near the winding cone at the end of the spring. Engage one end of a winding bar into one of the holes in the edge of the cone, so the winding bar is horizontal, then use a wrench to loosen the two bolts that secure the cone to the bar.
  3. Keeping a firm grip on the winding bar, allow the spring to slowly unwind until the winding bar is vertical below the spring. Now insert the second winding bar into the cone, lift it slightly, remove the first bar, and allow the spring to unwind another quarter-turn. Repeat the process until there is no remaining tension in the spring.
  4. Go to the opposite end of the spring and loosen the bolts on one half of the stationary cone that straddles the center bracket. Separate the two halves of the stationary cone. Clamp the vise grips onto the shaft at the center bracket to keep the shaft from slipping out of the bracket.
  5. Now go to the end of the torsion shaft and loosen the bolts on the cable drum. Remove the cable end from the drum and slide the drum back towards the center bracket. Repeat the process with the other cable drum at the opposite end of the shaft, slide the shaft out of the end bracket, and set aside the cable drum.
  6. Slide the old spring off of the shaft. And while you’re at it, this is the best time to replace the center bearing that sits in the center bracket and keeps the shaft and bracket from wearing each other down.
  7. Slide the new spring onto the shaft. (Pairs of torsion springs are made of right- and left-hand springs, so make sure you’re replacing the correct side. The end of the spring wire near the center bracket should come up and over from back to front on each side.) Go to the opposite end of the shaft and remove and replace the spring. Now slide both springs into the center, remove the vise-grips, and bolt the stationary cone halves together.
  8. Replace the cable drums at either end of the shaft, reinstall the cable onto the drums, make sure the cable is taut, and tighten the drum bolts back onto the shaft.
  9. The last step in this procedure is to put the tension back into the springs. Each spring may require 30-35 quarter-turns to be brought back to tension, but check the manufacturer’s recommendations for each model of spring. Each turn will be made in increments of a quarter-turn, just like the procedure you used to loosen the springs, but in reverse.
    Note: The tricky part is that, until the bolts on the winding cone are secured, the spring will want to unwind.
  10. Insert a winding bar into the winding cone and lift up on the end of the bar. While holding the first bar up, insert a second winding bar into the cone and lift, at the same time removing the first bar. Always remember to keep pressure on the upper bar until you’ve engaged the lower bar.
  11. When you’ve reached the required number of turns, maintain pressure on the winding bar and grab the wrench that you’ve cleverly stored in your back pocket and tighten the bolts on the winding cone. Repeat the process for the other spring.
  12. Reconnect the door to the opener and check the door’s operation. If the door doesn’t close all the way or won’t stay closed, you may have to readjust the tension on the cable drums.