245 5.0 the power steering pump groans. i just put a new pump in and the rack is a used unit. Both were put in at the same time. My question is should I go for another rack or is it likely the pump? I had no noise before the change but the steering was getting bad.

Every combination of rack and Ford pump I had in mine over 19 years (3 pumps, 2 racks - 1 CAM, 1 ZF) all whined. The Mustang guys complain about whining pumps all the time. I just told folks it was supercharged. I've read a procedure for drawing a vacuum on the reservoir while the engine is running to help pull trapped air out of the system - and one guy (just 1) that I could find who tried it and said it worked.

Yea, heard a lot of mustangs making the same noise, quite a few much louder.

I used the Volvo pump which rotated the correct way for the car. Used the 5.0 mounting bracket and a ZF rack on an 83 244.

If you peruse the 4x4 vendors, someone makes a kit to put a Saginaw (type GM and Volvo used) pump on the Fox body accessory bracket. One of the many benefits of replacing my 5.0L with an LS3 is the presence of a Saginaw pump which makes no noise at all.

I have to ask...why did you put a new pump? Was it something the old one was doing..or not doing? Why did you put in a new rack? What were the symptoms?

I put in the rack because turning one way the assist was lower, forget which way now. The pump-- I had a leak. That turned out to be the crappy high pressure fitting on the pump. Wife's car so I wanted to be thorough. That worked out well.