Busted bellhousing on Kubota B series

[ptsg]

I've owned 12 Kubota's now and none of them had cast steel bellhousings. All were CI.

Plenty of the Kubota B series tractors had formed sheet metal on the bellhousing, just like the OP's tractor.

 

[SDT]

That bellhousing looks to be formed steel rather than cast...maybe? If it is steel, cut the busted flange off 1/2" or so above the face to get rid of all the crud and have a new flange cut from 1/2" plate and weld to the housing. If you don't want to do the complete flange, jus t do the bad portion. No, it won't be cheap but probably cheaper than a new one.
As for the shaft sorta the same deal. It looks like there's a bit of shaft that's still good just before the splines to get a good size measurement. Cut it off, drill a small hole into the center of the remaining shaft and get an end machined up and weld it to the end of the shaft. There's no torque on the very end of the shaft.
Another option would be to have the very end of the shaft turned to accept a smaller Id bearing. Bad part about that is it would mean you'd have to disassemble the transmission. How's the OD of the bearing bore in the crank, chewed up as well or not bad?
Second look...those splines don't look very good.

It is steel.

Common on small tractors.

That tractor has been abused.

 

[YanmarFever]

On the bell housing, Cut to size, file to fit, weld on, and paint to match.

 

[mrmikey]

That tractor has been abused.

May have had a backhoe on it which will cause that kind of damage. Is that abuse...only if you try and do more than it was designed for or proceed to beat the crap out of it which it looks like in this case .

 

[5030]

Plenty of the Kubota B series tractors had formed sheet metal on the bellhousing, just like the OP's tractor.

News to me and his BH certainly don't appear to be sheet metal.

 

[ptsg]

News to me and his BH certainly don't appear to be sheet metal.

Look closer. You can even see the weld on the bung for the inspection plug.

Here is a picture from the B7000 I used to have. All sheet metal from the back of the engine to the transmission/rear end.

 

[Paystar]

Possibly the bolts came loose in the bell housing to cause that. I had a couple old 8V71 Detroits with 13 speed Road Rangers and the bell housing bolts always came loose.
That would break that bellhousing.

 

[5030]

Look closer. You can even see the weld on the bung for the inspection plug.

Here is a picture from the B7000 I used to have. All sheet metal from the back of the engine to the transmission/rear end.

View attachment 817528

You could be correct as I had no reason to take any of mine apart, but it looks pretty thick to be steel. Take one helluva press to form that as thick as it is. Least you painted it the right color...

No matter, I'd say that unit was flogged hard and more than once.

 

[CalG]

A front blade without a full push frame will do that.

I was warned as much regarding fitting a blade to my B7200. Someone had BTDT, and "learned me". ;-)

 

[jaxs]

Grey cast iron has a yield strength of anywhere between 9500 and 60,900 PSI. Brass is 18,000 to 45,000. Silicon bronze is 15,000 to 60,200. 655 silicon bronze is a common alloy and it has the 60,200 yield strength. This is not the ultimate strength but you really don't care about that, you care about when the part starts to yield, whether it is the original cast iron or the weld repair. Mild steel is about 60,000 PSI yield strength. If all you have is an oxy-acetylene torch then I would choose silicon bronze rod or regular brazing rod. There are cast iron stick welding rods that work well too. Stoody Castweld55 is one. It can weld steel to cast iron and do a good job. It will result in a very hard bead though. Suitable for grinding but not machining. No matter which process you use the housing should be preheated to at least 400 degrees. After welding or brazing the area should be covered with some sort of heat resistant insulation to let it cool slowly. I have used the Stoody rod, which is available at almost any good country hardware store, for several jobs and it has never failed. I even welded a Bush Hog gearbox to the frame of the Bush Hog after it started to break the frame. The frame was cracked about 320 degrees out of the 360 degrees. The weld still is holding after about 20 years. It was an emergency repair that was only supposed to last about 4 hours. No matter what you can, and should, use steel plate for the repair pieces. Don't bother trying to find cast iron pieces to fit into the spaces unless you have the original pieces. Besides replacing the input shaft you should replace the pilot bushing too. If the input shaft is not available then it should be machined back to round and then bushed with a hardened bushing back to size. The bushing should be a press fit or a shrink fit. A drill bushing could be used. Any decent machine shop will know what I am talking about. It could also be built up with weld and machined to size. But this will warp the end some so the original center in the shaft, if it has one, will no longer be in the center. A good machinist will know how to remedy this situation. I think that welding and machining or grinding to size, if the center needs to be reestablished, will be more expensive than machining for a drill bushing and buying the bushing. McMaster-Carr sells drill bushings and for the size you would need the cost would be less that 20 bucks plus shipping.
Good luck,
Eric

That's helpful,thanks. I tried wrangling information about metal alloy out of Kubota but their AI wasn't any help and dealer said "a good welder knows how it should be welded". Yea and reputable mfgrs know what alloys are used in their products.