how often do rear coil springs go bad?

[64stpside]

Originally Posted by The Rocknrod

I dont think bouncing is the springs, You may you need better (read Different) shocks.
The “bounce test” requires some effort. Go to one corner of the car and push down. When you let go, the car should bounce up, then settle back to at-rest height. If the car bounces more than twice, you most likely need new shocks.
Also a vid on the subject - https://www.youtube.com/watch?v=BiW0ISi8N-w

I talked with the front end guy here at work and he asked what kind of shocks I put on it. He's said if the shocks I got were heavy duty then that would cause a bounce with no load as the heavy dutys are meant for vehicles with a load on them. I gotta find out what I bought.