Had that done a few months back, $350.00

Incredibly dangerous, yet looks easy. IIRC someone in my city got killed doing those a year or two ago.

Ha, I didn't know I was such an expert DIYer. I've done two garages and found it pretty easy.

I went to a garage door company and asked for a used spring and they said help yourself the skip's over there.

Having watched a pro replace mine (less than $200), I'd be tempted to try it myself (now), but I knew enough to call a pro the first time around :)

I had one replaced a couple of years ago, I thought it a bargain at $140. The risk/reward ratio made it an easy choice.
Jim

Call someone, change both spring(s) on that door also, along with any other springs the same age.

The spring(s) needs to be properly sized, based on the weight of the door.

Anyone reading this thread that may have tension springs instead of torsion springs like this, make sure you have safety cables running through them, and change them if they are 10+ years old.

Piece of cake if you know what you are doing. If you don't then stay away.
The hardest part is getting a spring. Good luck buying one from a store, your best best is to get one on-line. You need to know diameter, length, and right or left hand lay.
I had to pay someone to do it once which pissed me off but I needed to get it fixed quickly and couldn't wait to have a spring shipped and couldn't buy one locally.

That place in Chicago seems like where I got mine last time and they were really cheap i.e. << $350. If I went to the door installers shop in town they were 4 x as much just to buy a spring. Obviously they didn't want me to do it.

Oh yeah, one thing that had me stymied for a while was how to get the dead spring off the cones. I have a huge pipe wrench that worked great.

Call someone. Homeowners have been killed by those springs.

I don't know...
Someone that can do all this $hit (http://rennlight.com/) probably has the core competencies taken care of.

I asked this forum the same thing when mine broke last year. Dual spring in fact. Pro charged $80 to fix and and greased and adjusted the drive for free. Watching him mess with it made me glad I called him. Didn't look like fun.

A typical spring costs around $40 and takes about 15 minutes to install.
If .... you know how to control the energy.
Tip for those whose spring hasn't broken yet. buy some motorcycle chain lube or whatever and lubricate the thing. Usually these springs break starting with a stress fracture that grows from a corrosion pit. Lube it up, keep it from rusting or wearing against itself and it will last a lot longer.

my brother bought them and we installed them in a few minutes

Not difficult, but potentially deadly or crippling if you are inattentive.

Replace both springs at the same time.

I can guarantee you that you are more likely to fall and fracture your skull in the bathroom than you are to get hurt in the garage, statistically speaking

Thanks for the feedback - I'm going to sub this one out...

my dad's company is a big manufacturer of garage doors in Aus

the spring is broken and needs replacing. best to call a pro as getting the right amount of tension on it is tricky

surface rust is a non-issue