The 50 series tractors were some of their best built stuff in my mind and it is most unfortunate JD made the decision to diminish part support on these machines. I remember when looking for a steering yoke for my 750 in case mine broke as the steering knuckle did, It was no longer available. I found one on ebay for $400. This was about an 8" piece of cast metal.
This lack of parts support only 20-25 years down the line, was key in making my decision to purchase a new tractor. Since Mahindra is using 3 different companies to build their stuff, no doubt 20 years down the line, I may find myself in the same boat (either that or a coffin as then the issue becomes moot to me)