Two months ago leak in line caused resivor to run dry, just for a few minutes.
Corrected and a month later started getting stiffness at the 2 and 10 o'clock positions. Told that steering rack is failing needed new one. Tried
all other remidies, still stiff, although sometimes not so. Here's the real
odd part, after driving throught heavy rain for 30-60 minutes the next day the stiffness is gone almost entirely. Stays that way for a day or so
then back to the same old.

Any ideas or suggestions as to why.

 

You replaced the pump?

When the pump ran out of fluid what happened?

Is is possible the pump was damaged or pieces of the pump entered the PS lines?

Raise the front wheels off the ground, then turn the wheel and check for stiffness.

Could be a bad steering column U-joint, location is bottom of steering shaft in engine compartment.