Did you purchase this tractor new? I just can't imagine that if there is a manufacturing defect in the tractor that it wouldn't be repaired under the factory warranty. Certainly, Messicks has enough sway with Kubota that if they identify a defect in manufacturing, that they could get it resolved, should they want to get involved. Warranties for defects can be repaired by any authorized Kubota dealership. Individual welded-on parts can be easily machined by any competent machine shop. Have you considered that route if you can't get satisfaction from Kubota?
I bought it new from an incompetent dealer. After several visits and then a six week spell where the dealer held the tractor for Kubota to get involved. At the end of that time, they said that the cylinder has been replaced (they lied), and had no clue on what the problem was with the dipper. I brought the thing home. Keep in mind that I correctly identified all of the problems on the first day of use. In order to use the backhoe, I made a temporary repair to the thumb adjustment in my machine shop. Yes, I know what I am doing, but I am not going to cut off major parts of a component and weld them back on over an inch from the original position, especially on a brand new machine.
I have ten pages of history on the issues, there is too much to share here. I emailed and called the useless
Kubota Contact and received absolutely no help. I then contacted Messick's and they agreed to make repairs. They called back when they had an identical unit for comparison, so I took it there and sure enough I was right all along. Messick's can't get the parts but they did rebuild the cylinder. After two weeks at Messick's they called and said I should take it home and they will call if and when parts are available.