Steering noise

[PFA]

I am having a steering noise at low RMPs. If I rev it a bit, it goes away. It's like a racketing noise, like something loose or popping. It will do it when just starting up or when steering but goes away as soon as I raise the RPMs. The system was apart for a motor swap. Could there be air in the line? or what???
Thanks

 

[SHOZ123]

If the reservoir is full then I doubt if it is air in the lines. I've never had any problems after draining the PS system. You could try going lock to lock a few times. This puts the highest pressure on the system and may dislodge any remaining air if that's the problem.

 

[PFA]

Still having this noise. It only happens at low RPM, mostly while turning, like into a parking space. It sounds like a loud rattling or a quick clinging back and forth. It sounds like something is loose and the low RPMs makes it rattle, like it is stress on it or something.
Iv'e turned it back and forth and while it's at its max, it does whine a bit, a totally different kind of noise.
Any more ideas???