The doors with two springs are easy to replace.
How to install a garage door side spring.
Disconnect the garage door opener so the door remains closed.
The springs extend along the shaft and work by twisting as the garage door closes by means of cables attached to each side of the lowest garage door panel.
There are two types of garage door springs.
Side mounted springs are long heavy springs mounted on each side of the upper garage door track.
This tension makes it easier to lift the garage door from its closed position.
A pair of new springs cost about 25.