Thanks for the help so far everyone. So I yanked out the rod and assembly. It tuns out whoever assembled this last put the valve pin ahead of the valve assembly for some reason, but that is what was causing the blockage apparently. The face seal was completely disintegrated, a chalky mess. Other than that everything looked to be in good condition, I'll try my luck at the hardware store and see if I can find another face seal.
One other thing I noticed was that when I pulled out the rod there was a collar on it secured with a set screw. I'm guessing that this is just to keep the rod centered in the bottom tube, does it serve any other purpose? Does it require any adjustment?