power steering wierdness

[RayG]

I have a question regarding steering on an '85 300SD. I found last night that if I turned hard left, nearly to the stop, there was an "over-center" sensation in the steering. I would get normal resistance and feel to the steering, ie. it wants to return to center. Cranked all the way to the left, I reached a point at which the resistance switched directions. I had to turn the wheel to the right to keep it from turning farther to the left on its own.

I have no other complaints. The car tracks straight going down the road. The upper control arms are new, and the lower ball joints and tie rod ends have no looseness that I can find.

Is this behavior normal?

Thanks,
RayG