First thing I would do is jack up the front of the car and place it on jack stands. Inspect all your mechanical linkage for wear. With the car on stands and the engine OFF turn the wheel lock to lock in both directions and see if it is still feeling like it binds. If not do it again with the engine running to be sure it is a hydraulic issue. Are the p/s control valve and ram original? Have you dbl checked the fluid level? Are you using the proper fluid? Any leaks? And if so from where?
Unfortunately the only place I believe you will find one is a wrecking yard, mine broke at the bend years ago, and I'm Still looking. I will probably just end up buying a repo assembly. Good luck.