Garage door spring replacement

One of the spring snapped on one of our garage doors this morning. It's a single car 7' tall aluminum door with a pair of linear-pull springs with cables & pulleys. How do I determine what strength springs I need. 

Wire diameter, coil diameter, and number of coils.  Never done linear-pull.  Had my neighbor help with the first one.  Called a pro when the second one let loose.  Easy button is call a pro.  If you poke around online you can probably find the info you need.

Edit:  Apparently, there's also a color code:

https://stigaragedoor.com/in-depth-guide-how-to-%D1%81hoose-garage-door-springs/#Extension_Springs

Agreed on getting a pro.  Garage door springs are nothing to mess with.

If you are replacing one, I urge you to reflect on the fact that the other spring has been through just as many cycles.

We hired someone. Was under $150 for parts and labor for one spring.  Can't beat that 

In reply to Mr_Asa :

I paid about the same to replace both springs as one snapped. It might have been $65 for each spring. 

Home Depot sells them by the pair, so that's my plan. I've replaced them before & reattached this one for now, but it's not safe for frequent use. If I knew anyone local I'd hire it out, but I refuse to call random companies for any service, as I've had nothing but bad luck and/or overpriced bills whenever I've done that in the past. . 

In our area there are guys that run specials for springs.  I agree I hate to call guys but this is one to call for.  

I am very handy (not JUST handsome), and stubbornly independent, but garage door work is one where I call The Man.

I know someone who nearly lost his eye and could have died messing with a garage door spring. The wrench he was using was never seen again. 
 

Not an idiot either, second generation owner of an auto repair shop, and one of the best I've encountered. 

Datsun310Guy said:

In our area there are guys that run specials for springs.  I agree I hate to call guys but this is one to call for.  

I have messed with them successfully, but some years back one of my springs broke during a stretch of subzero weather so I decided to pay someone else to do the work.  I was pleasantly surprised at how reasonable the cost was, and the tech who did the repair finished it in record time.

I have been on both sides. Needed a spring quick and the cost wasn't bad. Chose to do high lift and the quotes were nuts. Did it diy with a ddm kit and was one of the easier things I have done. Getting the bar for turning the springs made the job cake. 

I think he's talking about the linear/extension springs and not the torsion coil springs. The former are pretty easy to remove and reinstall when the door is open and most of the tension on the spring is released.

Installing safety cables would be a good idea if they aren't already there.  

Have done a bunch, never had an accident.  Yes do them in pairs, use the safety cables inside the spring and test it a half dozen times from outside the garage. Never saw one break and shoot thru the door.  

porschenut said:

Have done a bunch, never had an accident.  Yes do them in pairs, use the safety cables inside the spring and test it a half dozen times from outside the garage. Never saw one break and shoot thru the door.  

"shoot thru the door"... 

Yeah, I'm calling someone.

One broke on one of my doors so I replaced it.  Now it chatters going up & down, springs are not identical strength so one pulls harder than the other.  =~ (

Sometimes there is a color code marking on them for length. Buy them in pairs. It's a pretty easy job.

Datsun310Guy said:

In our area there are guys that run specials for springs. 

And the Spring season is just around the corner!