How do i replace torsion springs for a garage door?

It can be extremely hazardous. That being said, I've done a few tension springs (used on one-piece, swing-open doors) and a few more torsion springs, which are used on sectional doors. It doesn't require a lot of fancy tools, but it does require care. If you're not careful, you can hurt yourself. Ok, I know I said it before, but it can be Dangerous. The really important thing is to purchase the right springs for your door before you start. This can require putting a scale underneath your door and weighting it. Don't depend on matching the springs that were previously installed. Installers sometimes make mistakes. I could make a video of the process, but there are really good ones out there already. Just search "replace garage door tension" or "replace garage door torsion" and click on "video". If you watch a couple of them, you'll probably learn 99% of what you need to know.

My question is, why are you replacing the springs?? If they are not broken, I take it you just have a mess of cables wrapped around the shaft? The thing to do is, get the big vice grips, the big ones, and the pipe wrenches , clamp the shaft, straighten out the cables, then attempt to put tension on the springs, they have a colored stripe on them so you can make them the same amount of winds. You might have to release their tension to -0-, before you start. If you get it straightened out, get a bar of steel, 1/2 diameter, stick it in the torque master hole there and loosen the bolts, wind up as far as you can go,1/2 turn or so, tighten, go to other side, repeat, go back, repeat, eventually, the door will open by itself, then you have to loosen it up a hair so that it will go up with one finger. That way, the opener has no problem. Do not answer the phone while you are doing this. Fair warning.