One thing I remember on the early rack, the steering shaft into the upper joint had to be not quite flush with the inside of the joint. If the shaft extended at all, then the other half of the joint would contact it when turning because of the steep angles
Ok, I finally had some time to work on my stang and work on the r&p bind problem.
I decided to try to disconnect the rack to check if the problem could be inside the rack. So, I raised the car in the air and removed the connecting shaft. And guess what! When I grabbed the wheel and turned it manually, the same binding could be felt.
So, the problem is actually a quality problem with the Unisteer R&P itself!!
Next I will call Unisteer to check what to do. Let's see if they are willing to help.
Unisteer don't do any quality test of their R&P's, they only assemble them and check that they move. The answer from tech support was, that I should drive 500 miles and see if there is a difference. The pinion and rack normally needs to "wear in".
This rack goes out as soon as I get some money to by a better quality power rack!