PS pump help!

[Texasbigblock]

Hey everyone,
I'm in need of some help with my power steering. My power steering pump on my truck whines non stop. I've bled it by turning it lock to lock and just can't get the whine out. Also, the pump builds up extreme pressure to the point where it'll blow the cap off. The fluid always is foamy so I figured I must be getting air in somewhere but the pump doesn't leak a drop when the truck is off and sitting so It seems like there aren't any leaks in hoses or anything. Anybody have any ideas? The ps pump and hoses are only a couple years old. I've taken out the valve and checked it and everything is working fine there.

[AirSpeed]

Does tightening the belt help with the whine? Maybe clean the pulleys and belt. I had an issue with mine years ago, it was blowing fluid out but it turned out I had overfilled it.

[Texasbigblock]

The belt is tight and almost new, as are the pulleys. Even when the pump is almost dry it will still get foamy and push what little fluid it has in it, out so I know its not overfilled.

[GASoline71]

Some pumps just don't last. I replaced the PS pump in my truck 3 times in 3 years before I got one that wouldn't whine, and give me fits. That was 6 years ago, and it still works just fine.

I always install just the pump, and not the pump/reservoir combo.

Gary