3-Point Hitch Top link mount tore off back of differential case

cdaigle430 · Oct 2, 2020

I wouldnt let Kubota off the hook completely here...yes 3 point mount BH are not recommended but...this looks like a bad cast to me. If you can proof it at least they will warranty the parts.

California · Oct 2, 2020

jmc said:
On the closeup pic, that rusted, tapped hole is concerning. Just speculating- not likely water could get down in there on a tightened bolt. Loose bolt would completely change the stress distribution on that assembly.

Good eye!

After reading that I went and looked again at the pic in Post 12. I see a polished dimple next to the left, remaining, vertical bolt. Could that indicate that the bolt attaching the 3-point upper bracket, was bottomed out which made stress that pushed the back of the transmission off? That might be a basis for a warranty claim.

TMGT · Oct 2, 2020

The more I look at the pictures the more I'm wondering what happened, low hr tractor, BH that doesn't even looked like it was used. If it had been used heavily/abused I could see damage, but this looks like it failed after mounting?

I cant see any casting issues from the pictures, and the rust on that through hole is common (the washer above it is a split washer).

California · Oct 2, 2020

TMGT said:
low hr tractor, BH that doesn't even looked like it was used. ... this looks like it failed after mounting?

Paint on the bottom of the bucket and teeth is pristine, impossible if the bucket has ever been in the ground.

TMGT · Oct 2, 2020

California said:
Paint on the bottom of the bucket and teeth is pristine, impossible if the bucket has ever been in the ground.

Exactly, and that dimple you referenced is the bottom of the drilled hole for the horizontal bolt, doesn't appear to have had a bolt bottomed out in it.

I hope the OP can shed some light on what caused this, or at least the circumstances that led up to it.

TMGT · Oct 2, 2020

I actually just noticed something, there is a second pin in the top link bracket, with the larger solid top link of the BH I wonder if the BH top link bound on that second pin.

That could possibly put the full weight of the BH in a torsional load on the top link mount, which it is NOT designed to handle. One good bump and I could see it breaking if it didn't immediately. The way the casting is broken looks to support that type of loading.

Henro · Oct 2, 2020

I feel for the OP. What a bad situation!

But I am wondering what the manual for the tractor states regarding attaching a backhoe to it. I know with my B2910, it requires a heavy duty top link bracket if a 3PH backhoe is attached. Been using my 3PH backhoe for 18 years without an issue, But that is just me.

No doubt that a sub frame mounted backhoe is a better setup.

Do the manuals for more recent tractors than mine, which was purchased in 2002, prohibit use of a 3PH backhoe?

Curious more than anything...

jmc · Oct 2, 2020

TMGT said:
The more I look at the pictures the more I'm wondering what happened, low hr tractor, BH that doesn't even looked like it was used. If it had been used heavily/abused I could see damage, but this looks like it failed after mounting?

I cant see any casting issues from the pictures, and the rust on that through hole is common (the washer above it is a split washer).

That's fair. I'd like to see the bolt/tapped hole on the other side though.

With a loose bolt, just the cantilevered weight of the bh driving down the road could reek havoc.

TMGT · Oct 2, 2020

jmc said:
That's fair. I'd like to see the bolt/tapped hole on the other side though.

With a loose bolt, just the cantilevered weight of the bh driving down the road could reek havoc.

Do you mean the bolt going straight down?

I've pulled the 3pt hat off a couple Kubota compacts and the through holes on the hat have always had some corrosion in them. Based on the corrosion on the 3pt balls etc. I'm guessing it lived outside for some of its life

deezler · Oct 2, 2020

TMGT said:
I actually just noticed something, there is a second pin in the top link bracket, with the larger solid top link of the BH I wonder if the BH top link bound on that second pin.

That could possibly put the full weight of the BH in a torsional load on the top link mount, which it is NOT designed to handle. One good bump and I could see it breaking if it didn't immediately. The way the casting is broken looks to support that type of loading.

This is an intelligent hypothesis. A picture of the bottom of that backhoe's top link could show if the paint was rubbed where it would have contact the second, lower top-link pin that was left in the mount there.