Main thing is you need to jack the body of the truck to relieve the pressure from the support point of the spring. This will make it easy to remove the shackle and the pivot bolt. If your spring is broken at the support/pivot - not so much of a problem but you still need to jack the body.
Here is a post about my experience replacing spings on my '51 1/T. I have a picture of how I jacked the body in this post.
Replacing springs Note: I really think you should consider replacing ALL your springs given the fact one has broken. Certainly you should replace the one on the other side. Otherwise your steering will be very wonky.
You can make a puller/installer from pipe parts and threaded rod for the bushings in the frame attachment points.
Kurt
