MF 205-4 Steering Problem

Hello. My MF 205-4 has a steering problem. I hope someone out there can help! The basic problem is that it can steer to the left fine but not to the right. (This would be ok if I only needed to go in circles!)

I have disconnected the steering linkage to check the movement of the individual wheels. Wheels move fine.

It has manual steering.

Thanks in advance for your thoughts. Brian