Hello all. I just picked up a Grand Jubilee. My very first tractor. It seems I need to do something about the rear wheels (original) but I'm not sure what. One of them, especially, is going flat. The previous owner, a very nice guy, told me to get the tubes replaced because the salt water solution had corroded the valves. On the leaky one, that is very obvious. Is this something that would be an obvious problem and solution for an Ag tire shop? Is there any book that would help me understand how these wheels/tires go together/function? Any advice would be greatly appreciated.