Suction in Power Steering Pump?

[Lumpo]

I have a 2003 and I noticed power steering struggling so I replaced the pump with no change. I know I have magnasteer and I know it's not working I have only about 60% power steering. Also noticed when I open my power steering cap it's building alot of suction and then it will work much better till the air builds back up. Am I suppose to have a venter cap on the power steering with magnasteer or what's going on here?

[Lumpo]

Delete this please.