I attempted an almost identical repair like this once and ended up in the ER. Don't do it. Call a pro.
How I replaced deadly garage door torsion springs (2002)
231–240 of 344 posts
Re: How I replaced deadly garage door torsion springs (2002)
#232Reminds me of the old engineer joke: "Did you know you can save $27.00 if you build your own refrigerator?"
How is this the first time I have heard this? Just golden wisdom that is broadly applicable to so much DIY.
Re: How I replaced deadly garage door torsion springs (2002)
#233I had a teacher in high school who was blinded (I think only in one eye) trying to do this repair. You could not pay me enough money to do this repair. >This work is risky, but the risk is comparable to doing your own car repairs, or climbing on the roof of your house to clean your gutters. Notably, "unintentional fall" is the #1 cause of emergency department visits for adults [1], which is why I'd hire a professiona…
I don’t understand why it’s even considered safe to have one of these springs in one’s garage without a solid shield of some sort. While the energy involved is small on the scale of energy storage devices ( Which brings to mind some rather different designs. A rather small motor with a lot of mechanical advantage can easily open a close a garage door, and if a DC or low voltage AC motor is used, it could do so quite…
> I don’t understand why it’s even considered safe to have one of these springs in one’s garage without a solid shield of some sort.
The shield is the steel tube that runs down the middle of the spring. When the spring breaks, it's got an integral safety containment, similar to the aircraft cable that is often run through extension style springs (which are probably far more dangerous when they break, though less dangerous to service).
> I’m honestly not sure why springs are common at all in this application.
They're nicely matched to the load profile of the door. As the door is fully closed, the spring is exerting maximum upward force. As sections of the door transition to the horizontal track, the spring is simultaneously relaxing some, meaning it exerts around half the force when the door is halfway up and very little force as the last segment hits the turn in the track. It's a pretty elegant match of mechanism to the load profile.
Re: How I replaced deadly garage door torsion springs (2002)
#234Earlier quoted context omitted.
They exist, but are not connected to anything. It just swings on the rollers.
The springs are different than the opener. I don’t think the springs can be disconnected, they have to be carefully removed. You would know if they were or were broken, because you couldn’t open the garage door.
Side-mounted extension springs can be easily disconnected with the door up (and ideally clamped). GP describing them as "not connected to anything" makes me suspect that they're extension springs, which can be easily/casually inspected and determined to be not hooked up to anything. Torsion springs you probably need to look to see the marks on the spring wind up (or make a straight chalk mark on it and see if that twists uniformly).
Re: How I replaced deadly garage door torsion springs (2002)
#235Earlier quoted context omitted.
I knew someone in high school who had started work at an auto repair place, and he described the process - and danger - of replacing car springs to me once. I'm sure there are various types of car spring, the kind he was talking about was the stereotypical coil-of-metal spring. There's so much energy in there that a small slip up can be deadly.
It used to be worse. Lots of cars today use a coil-over-strut design that captures the spring. There's still a lot of energy, but it's much easier to manage safely, by the time the nut at the top runs out of threads there's generally little to no force left in the spring. Way back (like... 30 years ago) when I was working on my Mustang, the spring was separate from the strut. You had to drop the control arm enough to…
> by the time the nut at the top [of a McPherson strut] runs out of threads there's generally little to no force left in the spring
This might be true on heavily lowered cars, but cars at stock ride height [with stock springs IOW] this is not my experience at all. I sure wouldn't risk my life or limb on it and spring compressors are quite cheap compared to an ER co-pay.
Re: How I replaced deadly garage door torsion springs (2002)
#236I'll agree with Reddit and most of the posts here. It's too dangerous to be worth it. Once every 3-7 years replacement at ~US$150-350 YMMV is honestly not that much money saved vs the risk.
Once every 3-7 years? I've heard of them breaking before but I've never had it happen in a place I lived, including my parents' house growing up, and the houses I've personally owned. I've never had the spring worked on other than to have it installed in the first place.
Again, I know they break sometimes. It should not be happening every few years.
(But if/when it does, take my money. I'll replace my car's brakes and wire a new ceiling fan but I'm not touching that spring for love nor money.)
Re: How I replaced deadly garage door torsion springs (2002)
#237Earlier quoted context omitted.
How does a counterweight work? A torsion spring is great because as it unwinds, the tension decreases. As the garage door transitions from 200 lbs of vertical load in the closed position to almost 0 lbs when it's mostly parallel to the ceiling, a properly sized and wound spring reduces the force in synchrony with the door position. Wouldn't a counterweight provide insufficient force at the bottom and/or excess force…
It’s like for an elevator. The motor is there for the friction but the potential energy of the system is approximately constant.
An elevator on the ground floor and an elevator at the top floor have the "same" weight.
Not so for a 100%, 50%, and 0% open garage door. The 0% open door is the full weight; the 100% open door has very little weight (as most of the door is on the horizontal track).
Re: How I replaced deadly garage door torsion springs (2002)
#238Earlier quoted context omitted.
> A rather small motor with a lot of mechanical advantage can easily open a close a garage door, and if a DC or low voltage AC motor is used, it could do so quite a few times even if the power goes out. Garage doors are actually fairly heavy. By balancing the weight with a spring, you do a lot of favors to your mechanical advantage systems. (Eg: less wear, less advantage needed, the door can open in a reasonable amou…
What about a counterweight or a piston instead (pistons are used in pull down beds which might be a similar load)
See sibling comment above about the variable counterbalance needed for a normal right-angle tracked garage door.
You'd have to match the counterweight to the varying load (i.e. garage door effectively gets "lighter" the more its raised).
Re: How I replaced deadly garage door torsion springs (2002)
#239Earlier quoted context omitted.
Still need to store the same amount of energy. A counter weight or piston also has more opportunities for uncontained failure. At least when a garage door spring fails it is still constrained by the shaft running through the middle. For what it's worth, I have also replaced my own garage door spring, and I really have no desire to do that again.
The risk isn’t just what the spring does but what happens to something caught in it. Springs can release energy a lot more quickly than a counterweight which can only accelerate a 9.8m/s/s, and therefore more risky to disable.
A few hundred points accelerating at 1g is still plenty of energy. It also comes with it's own challenges when it comes to releasing it.
It also provides a constant force, whereas the force required to raise a garage door linearly decreases the higher it gets. With the consequence that a garage door with a failed motor would slam into its stops over your head rather then into the ground. Followed shortly thereafter by the now liberated counterweight slamming into the ground.
https://www.physics.smu.edu/scalise/www/misc/bricks.html
*Wrong link
Re: How I replaced deadly garage door torsion springs (2002)
#240Earlier quoted context omitted.
I’m not an expert in how springs break but wouldn’t an ejection of material require the spring breaking in at least 2 places that are close enough to not loop around the rod? I’m curious if anyone’s ever been hurt by one breaking (other than when actively working on it).
I’ve also never heard of a shrapnel-based injury. Only door falls or torsion bars breaking arms. I’ve actually replaced these in two houses, and yes, they’re dangerous, but honestly a little common sense and a straightforward (printed, with a buddy double-checking) list of steps you take with each quarter turn. It’s super important to have the right torsion bars. Don’t try to invent your own.
I am a terrible person and have done this twice with a couple angle-ground pieces of rebar (almost perfect diameter) + a pair of vice grips.
On the one hand, nothing went wrong because I was careful. And rebar actually works really well.
On the other hand, it was pretty dicey, especially near the maximally-wound state when you're putting serious muscle into another quarter turn.
110% agreed on it being a 2 person job though. Reason #1: so someone is there to call 911. Reason #2: you'll need someone to cable up the drums while you're adjusting the spring, and it's way easier with 2 pairs of hands.