foaming power steering fluid

[oldgreygoat]

I changed the power steering pump out on my 3/4 ton that has hydro-boost brakes. the pump I took off was one that has the remote fluid container. I changed to one that is self contained fluid. my problem is when I started it up and turned the wheel, it jerked, and sounded like it was way low on fluid. I cut it off, and took the cap off to check, and pink foam just poured out, I assume its getting air in it somewhere, but it wasn't leaking anywhere, so all the fitting were tight. anyone had this problem, I'm stumped as to what it is causing it. any help ??