70 Mach I Power steering problem

I'm about done with the 351 C Mach I. The p.s works sometimes but most of the time it shoots the fluid out of the top. I know the lines are correct but swapped the ones at the control valve just for the heck of it which didn't work, but when I swapped them back it did work. The control valve is new as are all the hoses. The P.S pump sit for 3 years.

Any suggestions?

Thanks,

Don't know anything about checking the pressure out of the ps pump. This is a 3 year restoration, the first start the PS worked on one side, then after I reversed the lines and then put them back it worked fine. When I drove it for the first time about a mile, it blew out the fluid. I tried to do everything right so I wouldn't have problems like this, oh well, it is what it is. I'm sure I'll get it figured out eventually.

Thanks for responding, I'll try that. Right now I think I'll let it sit.