Anyone see this casting break?

[Uiucbsme]

or...
maybe the mower is too big/ too heavy ?

If the mower is too big, the tractor has no business having a three point hitch. I got the smallest mower I could. The mower deck is the same width as the rear wheelbase.

 

[Uiucbsme]

Curious.looked it up, that casting is about $1300 Canadian, seems kinday easy to replace BUT the big issue would be to remove any casting bits out of the internal area.

I’m glad the break occurred while the tractor was off. Less likely to have ingested casting bits.

 

[TheOldHokie]

If the mower is too big, the tractor has no business having a three point hitch. I got the smallest mower I could. The mower deck is the same width as the rear wheelbase. View attachment 128810

If the mower is too big and the fracture is caused by overpressure the hydraulics are poorly designed.

If the fracture is caused by an impact that left the divot @hagrid noticed the problem is operator error.

Dan

 

[Mikeymotorbikey]

This is indeed the 3 point lift cylinder casting, $1072 at Messicks in the US.
There is a system relief valve built into the loader valve that's set at 1890-2000psi. Shouldn't this protect the casting?
Now, if the drop speed valve was closed completely and one introduced a bounce into a 3 point implement, I can see where a hydraulic shock load could be introduced.

 

[TheOldHokie]

This is indeed the 3 point lift cylinder casting, $1072 at Messicks in the US.
There is a system relief valve built into the loader valve that's set at 1890-2000psi. Shouldn't this protect the casting?
Now, if the drop speed valve was closed completely and one introduced a bounce into a 3 point implement, I can see where a hydraulic shock load could be introduced.

No. When the 3pt is raised and stationary the 3pt spool is closed. In tjat state the lift circuit is isolated from the main relief and unprotected from hydraulic shock loads.

To protect the lift circuit from shock loads a secondary "safety relief" is placed on the piston side of the valve. The cracking pressure of that relief is typically set a bit higher than the main system relief and only comes into play when some external event overloads the circuit.

In their infinite wisdom Kubota has no safety relief on the B series.

Dan

 

[Tx Jim]

Rockshaft piston housings normally have a thermal relief valve installed to keep that catastrophe from happening. I advise to check for presence & correct operation of TRV. I also was taught many years ago to lower all hyd attachments when not using or storing tractor.

 

[TheOldHokie]

Rockshaft piston housings normally have a thermal relief valve installed to keep that catastrophe from happening. I advise to check for presence & correct operation of TRV. I also was taught many years ago to lower all hyd attachments when not using or storing tractor.

Thermal? I have looked and there is no safety relief, thermal or otherwise, on that tractor's 3pt lift.

Dan

 

[Tx Jim]

Thermal? I have looked and there is no safety relief, thermal or otherwise, on that tractor's 3pt lift.

Dan

What do you think the purpose of item 150 in photo below happens to be?

 

[mikester]

If the mower is too big and the fracture is caused by overpressure the hydraulics are poorly designed.

If the fracture is caused by an impact that left the divot @hagrid noticed the problem is operator error.

Dan

I'd be more inclined to suspect that there was a blade or a plow getting caught on something while driving too fast. Casting looks a little light all around. I would expect an inclusion in the sand casting being the stress raiser. Joys of SCUT

 

[TheOldHokie]

What do you think the purpose of item 150 in photo below happens to be?

Unloading valve for "shockless" position control?

According to the WSM it cushions the shock of the spool closing as it comes to the neutral position. It is actuated by the pressure differental across the gland on the spool as it gets close to closing off the port. If it also functions as a safety relief its not discussed in the WSM or clear from the circuit diagrams

 

[GreensvilleJay]

Even the mower in post #021 looks 'heavy' IF you're carrying it instead of 'towing' it.
I was taught to 'tow 'n mow', only lift for short operations NOT to carry it. For some reason the fields where bushhogs are used aren't pool table smooth......
Any(ALL) humpty-dumpty bumps would impart severe stress to the 3PH 'stuff'.......

 

[jaxs]

I'm surprised that more tractors don't crack. Seeing little tractors on dealer lots wearing heavy implements front and rear is so common owners think it's ok to use tractors like that. Monkey see monkey do doesn't make it a good idea. Ordering or adding quick attach then leaving bucket off when not being used will save a lot of wear and tear. Having weight far out in front and rear results in leverage forces greater than tractor is designed to withstand.

A classic example of owners/operators being unable to see the forest for trees is all the discussions about mowing hillsides. Instability is exacerbated by tractor being overburdened so the solution is removing hoe or fel,not the addition of an incline meter.

Such a shame seeing a like new tractor with this damage. I've noticed several instances where Kubota used cast steel rather than cast iron. That could be important in repair. if housing can be welded back together cast steel is much easier than cast iron. I suggest having several configurations of magnets on hand to grab metal bits during repair. Parts washer is a must.

 

[GeoHorn]

I’ve never seen cast iron that wasn’t magnetic.…but I’m still young at 75.

I’ve seen two instances of this type damage…both of them by operators who travelled long distances between fields carrying heavy implements up/off the ground…. on of them having “chained” the implement up to the dogbone….the other using the hyds.

That pic looks like a pretty big shredder for that little machine…. but dealers happily sell those combos when they should be recommending larger tractors.

 

[MapleLeafFarmer]

or...
maybe the mower is too big/ too heavy ?

agree could be cause also maybe in concert with moving too fast over rough ground with implement lifted? the dreaded death bounce.

I have seen more than a couple of times over the years operator going too fast with rear implement lifted off the ground.

Hit a bump or some rough ground with implement lifted especially when moving at too much speed and the implement bounces causing huge forces downward far in excess of weight of implement.

causes expensive ouches' quickly.

 

[TheOldHokie]

agree could be cause also maybe in concert with moving too fast over rough ground with implement lifted? the dreaded death bounce.

I have seen more than a couple of times over the years operator going too fast with rear implement lifted off the ground.

Hit a bump or some rough ground with implement lifted especially when moving at too much speed and the implement bounces causing huge forces downward far in excess of weight of implement.

causes expensive ouches' quickly.

The whole purpose of the safety valve is to cushion and largely eliminate those huge forces.

Dan

 

[jaxs]

I’ve never seen cast iron that wasn’t magnetic.…but I’m still young at 75.

I’ve seen two instances of this type damage…both of them by operators who travelled long distances between fields carrying heavy implements up/off the ground…. on of them having “chained” the implement up to the dogbone….the other using the hyds.

That pic looks like a pretty big shredder for that little machine…. but dealers happily sell those combos when they should be recommending larger tractors.

You are right and I fixed it. I had brain farts while thinking of welding and heat treating.

 

[NorthwoodsLife]

I am probably wrong but I was under the impression that the B, LX and Grands use aluminum gear boxes, transmissions, etc. ??

And the L's and MX and M's are cast iron?

 

[TheOldHokie]

I am probably wrong but I was under the impression that the B, LX and Grands use aluminum gear boxes, transmissions, etc. ??

And the L's and MX and M's are cast iron?

The broken part is the hydraulic cylinder case. Its the top cover on the differential case.

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