Ed, that is as I remember the drawings of CAT steering; and that is why I was confused by your statement ". . . I'm not aware of any of the US tractors using a hydraulic valve to steer with."  I assume this later post was at least a partial retraction of that statment.

It appears to me that these CATs are one of the better examples of a steering system totally dependent on hydraulic valves; I also appears that you are almost in total agreement with Phil, at least until someone can site an example of a system that wouldn't perform better without hydraulic steering.  I'm afraid the old JD D would turn too hard for the EZ Steer.

One day I'll surprise you and take you up on that farming offer.  I'd enjoy doing it if I could get away!

Gary