Dealer has it apart, waiting for 1 more pump. Asked what could have made both pumps out and he said they were discussing it this morning. Only conclusion is it just got hot. I dig wide open for hours at a time. Anyways I said I want to go back with super udt even if kubota won't pay for it I will pay the extra. Not sure it's the answer but it can't hurt. I run it hard but not like an idiot, I stay onto on all maintenance. Changed hydro fluid and filters for first 50. Anyways I suffer from impatience and just want to know if this will happen again. It's a great machine. Does anyone else here dig ditches with theirs? What rpm do you run? I dig at 2500rpms.
So they think it was a heat problem? Well, I guess I don't find that too surprising.
In the operating manual, Kubota clearly states that the backhoe is rated for operation at full rated RPM (2700). There aren't any cautions about how long or how hard to work it at that RPM. So it sounds to me like you were operating within the rating even for hours at a time. Except it sure didn't work out.
We've got a pretty active group of
M59 owners here on tractorbynet, and this is the first that any pump problems have been mentioned.
Somehow yours got too hot. But how? Well, how about some speculation? Of course the the pumps could have been badly manufactured. Mistakes do happen without fault or blame. Since no other
M59 owners have reported problems with the then that's probably it. It's also possible - though less likely - that Kubota misfigured the heating/cooling capacity of their hydraulic system. Frankly, speaking as an older and senior mechanical engineer I doubt that's the cause. Designing for heat transfer is basic and well understood. And not only would they have to miss some basic calculations, but the standard heat rise tests every company does during product development would also have had to be ignored.
So if a system isn't creating too much heat, then the problem would have to be that it isn't getting rid of the heat generated by normal operation. There could be a plugged cooling loop somewhere. I haven't even looked to see where the cooling loops are in that system but you can bet that it has them. Even more rare would be if something happened to reduce the coefficient of heat transfer of the hydraulic fluid itself. That would be pretty far out in left field, but would sure cause the same problem. It would have to be something like a specialized hydraulic fluid designed for low ambient temperatures. Again, not likely.
Either way, if it had happened to my
M59 I'd be taking the time to find out what temperature Kubota wants their hydrualic system to operate at, and putting a temperature gauge in the hydraulic circuit. Any shop can do that. In fact I might do thaton my machine anyway. No point in repeating a repair.
What else...Oh, you asked what kind of digging other M59s do. I use it on our land instead of commercially like you do. But that wouldn't stop me from taking a commercial job if one came up. And I'd expect the machine to do its part without complaint. At home I tend to dig at 50/60% of rated RPM. On a job, I'd probably run it faster.
Good luck and thanks for keeping us posted
rScotty
