[Terry, NJ]

Be Very careful of the springs! I'm sure that in the history of model A s, someone has been killed by the rear spring. I almost lost a leg to one. DO NOT LOOSEN the SPRING UNLESS YOU HAVE IT CONTAINED!
To return to the subject at hand, here's what I would do; With the body in place, loosen the center nut on the spring. Back it off no more than two turns. Now flood the little gaps between the leaves with motor oil in a squeeze can.Maybe jack the frame (not the wheels) a click or three and get as much oil in between the leaves as is possible. Then let it all down on the ground again and retighten the center bolt of the spring. This is far easier and less dangerous than messing around with the spring.
Terry