Leaks on a hydraulic system can cause aeration of the fluid. The fluid will to fluffy and not create a solid hydraulic pressure.
That would need to be addressed. If you look into the PS reservoir does the fluid look airy/fluffy bubbly? It should just look
like PS fluid that has been just poured in. If the system had no fluid when the lines were pulled the system has air or your not
circulating. can you see flow in the reservoir? It sounds like the fluid is aerating on you. This is why the steering feels good when
first running and after running its aerating. Fix the leaks and see if the problem goes away. Look at the fluid before you start the car.
should look like oil without the air.