Purchase new garage door extension springs.
How to change a garage door extension spring.
Detach the cable and thread it around the pulley to free the spring.
You may need to use a 2x4 or some other object to pry the garage door open.
At the far end of the door rail remove the spring end from its mounting pin.
This video will show you how to replace the extension springs on your garage door.
Place scale under the garage door on the side of the door with the broken extension spring.
The following steps will walk you through how to replace an extension garage door spring.
The new spring s diameter length and wire size or gauge must be the same as your old spring.
Open the garage door to remove all spring tension and clamp it in place.
The easiest way to do this is to take the broken spring to a local garage door dealer or home improvement center so they can help you find an exact match.
Disengage the broken extension spring one end at a time.