B2710 Hitch Explosion

[KubotaTech]

I am working on a B2710 that now has a "removal hardtop" for a hitch cover. Looks like the hitch was on high relief. The small steel plate inside the cover that the internal hitch arm stops against is bent, the feedback rod is snapped off, and the front of the hitch cylinder is blown off with hyd. fluid all over it. The tractor has 200 hours on it, and I think it all happened from the feedback rod pivot being rusted and activating the hitch valve continuously. Anybody else heard of this? Any other ideas?

 

[KubotaTech]

I wasnt actually driving the tractor, it is one I am working on. The tractor has a three point adaptor with a hitch ball to move trailers around, not sure what size. It is a 2 inch ball, so nothing too terribly large.

 

[KubotaTech]

Did a little more investigating, found out this tractor does not have a hitch overload valve. Some of the early serial number tractors were built without an overload valve, which the new tractors are equipped with.

 

[traildust]

Did a little more investigating, found out this tractor does not have a hitch overload valve. Some of the early serial number tractors were built without an overload valve, which the new tractors are equipped with.

In basic terms, the hydraulics didn't have a by pass valve built in thus the tractor destroyed itself. Is that right?

 

[KubotaTech]

Well, I found out my information may not be correct, there is a relief valve built into the top cover. I'll find out for sure and repost.

 

[KubotaTech]

OK, I found out the relief valve in the top cover is the hyd. pump relief valve. So in theory the pressure in the hitch cylinder should never be higher than the max. hydraulic pressure, which is around 1990 psi. I talked to tech support and they said because the feedback rod pivot was rusted, the rod broke and the hitch valve was stuck in the up position, until the thing blew apart

 

[traildust]

OK, I found out the relief valve in the top cover is the hyd. pump relief valve. So in theory the pressure in the hitch cylinder should never be higher than the max. hydraulic pressure, which is around 1990 psi. I talked to tech support and they said because the feedback rod pivot was rusted, the rod broke and the hitch valve was stuck in the up position, until the thing blew apart

So then, for the most part you were right. Right?