What should be behind the large spring that I took out with a plug holding it in? I think there should be a piston or something but nothing came out but the spring unless it is stuck in there. 270 Dodge Poly pump.
Yep, the relief valve plunger should be behind the spring. It's probably gummed up and stuck in there.
Thanks, I finally got it cleaned up enough to see it and had to soak it for a couple of days and work it back and forth but I got it out. Cleaned it up and got it to where it would slide in and out freely. Rebuilt the pump and it is ready for the re-install!