Case cx160b no fuel pressure

I have been scratching my head on this for a while. We have a case cx160b in the shop with no lift pump pressure. So far I have tried multiple lift pumps, bypassing the tank and all the filters using a jerry can. Used all new hoses. I have put a new pressure relieving bolt in the lift pump lines. No luck.

If I block off the return line I can make it build pressure... the only part between the feed side and return is that bolt. I have tried 2 new ones. There has to be something stupid...

Case cx160b no fuel pressure

Case cx160b no fuel pressure