1841 Steering Problem

The first item that needs attention is the power steering. The tractor has a cable system power steering and when the tractor is steered hard to the right, the front wheels hang up and no amount of steering wheel turn will bring them back to center. This does not happen when the tractor is steered hard to the left - the wheels do not turn as far left as they did to the right, but they will return to center. When the front wheels are stuck to the right, I can manually activate the valve on the steering cylinder to free the wheels ( I don't believe there is a mechanical problem with the steering or front axle that is causing the wheels to stick). Any ideas on what is happening? The cables seem to be okay, they are not bent and operate freely.

Anyway, does anyone have any experience with this cable steering system. I have not tried to find any parts - the steering cylinder leaks also - because I was hoping to get some advice on whether it would be easier to repair this system or to replace it with a more modern system if possible. Has anyone replaced the cable system with something better. I have fair mechanical ability and can probably tackle the work myself, but I sure would be willing to listen to whatever others have to say before I do. I believe this steering system was used on other model Ford tractors in the late 50's.