Bill..... yes the wheels hit the stops in both directions.
Kevin...... I doubt the steering box has ever been opened. Not by me or the original owner. I read the rebuild instructions and , ya, they're pretty adamant about taking care of the balls. A bit daunting actually but I suppose I'll have to get in there.
As I said, after returning to the garage the steering wheel was back in its original position. With the front end on jacks, I can't reproduce the problem. I'm an old man so maybe it was all in my mind.