Power steering goes out intermittently

[Rumple]

I have an issue where the power steering goes out after driving for awhile. Initially after startup it acts normal. Then after driving around for awhile it goes dead and it's worse than manual steering. Turn off the engine and let it cool down and its normal again. This started after I replaced the power steering pump, pulley, and hoses. Didn't have this issue before the new pump.
The fluid is clear - I flushed the system. I've checked the fluid reservoir when the steering has this issue and I don't see any entrapped air.
Anyone experience this before? Could I have received a bad pump? Could this be a symptom of a bad steering box?

[dodj]

I'm going to guess at fluid, collapsing or somewhat plugged or kinked return hose, new pump is bad.

[Cuda_mark]

Could also be the wrong sized belt that sits to far into the pulley.