Kubota B21 backhoe axle bearings

Thu Apr 21, 2011 8:37 am

I've never seen a bearing broke like this before :!:

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Its been leaking for a few years and I thought it was a hyd line to the outriggers. Until my friend Scott grabbed and wiggled the tire when I had it jacked up digging a trench.

I don't know how it got broke but I have a feeling its one of two things. One when I first started working on our place I was putting in ditches buried to the axles in mud and could only move by pushing with the back hoe and curling the bucket and when I was trenching I could not get to solid material with the out riggers so a lot of the weight of digging went on the axle. Or two and most likely my Uncle had it and was square baling hay and dropping the bales in the field rather than hooking up a hay wagon. And having his 14 yr old son pick them up one at a time and take them to the barn. And he was doing it full speed hitting dead furrows jumping them with the tractor bouncing in the air. :headbang I wish I had been there and seen it their ears would still be ringing :!:

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It sure was a pain taking this thing apart. Had to pull off the whole loader backhoe subframe. 37 1/2" to 5/8" bolts (I don't know what the actual metric size is) on each side. Plus a bunch of smaller stuff. Then as I was pulling it apart I found I had no where to put jack stands that would not hurt anything else. So I ended up having to suspend the thing from hoists overhead.

I hope I can find somewhere else to get the bearings and seals from other than the kubota dealer. I ordered a service manual a week ago and told them I would pay shipping to get it as soon asap. And they said I may get it friday. Who knows how long bearings and seals will take :!: I have work I have to get done and I need it back together.

When its up and running its a great little machine :!:

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Billy

Re: Kubota B21 backhoe axle bearings

Thu Apr 21, 2011 9:08 am

Billy,

Good luck obtaining the parts and getting it back together!

It kind of makes you appreciate the simplicity of a Cub doesn’t it!

Re: Kubota B21 backhoe axle bearings

Thu Apr 21, 2011 11:51 am

Hello Billy, Just my 2 cents on the bearings and the seals. You can most likely get the bearings and seals at a good bearing store like Motion Industries, Applied Industrial Tech., Kaman Industrial, etc. Even Grainger, perhaps. These are usually metric measurements if no numbers are to be found. Measure accurately and you should have no problem. Also note, the bearing you have in the picture is an "open" type. No seals or shields. It is also a standard radial bearing in that it has the standard number of balls for its size. You can most likely get a "max" bearing for this application. It will have a greater capacity. Only limiter might be rpm. In your case, shaft speed here would probably not be an issue. I'd shoot for the "max" bearing if it were mine, only a few dollars more. Also, check to see if a shielded bearing would keep any junk out of it. "Shielded" allows oil to the bearing where a "sealed" bearing does not. Even a shield on one side may be of value. Question would be if it runs in oil or not. And, can it be greased, etc.
I offer this observance only from 40 years of working in the bearing and power transmission industry and only with limited input based on your post.
Good luck! Steve K.

Re: Kubota B21 backhoe axle bearings

Thu Apr 21, 2011 8:46 pm

Billy,

I'm sure that there is a bearing supply house in Adrin or Monroe. If you take the bearings to a bearing supply house, they will be able to match up a set of bearings for you likely cheaper than Kubota.

Re: Kubota B21 backhoe axle bearings

Fri Apr 22, 2011 6:48 am

Howdy David

Actually once I got the loader frame out of the way it was simple to get apart. It just takes time to figure it out.

Thanks Steve

I never knew there was a Max bearing I'll look into that :!: The bearings are inside the trans-axle and are oil bath.

Thanks Ricky

I am thinking of having my brother try to get them he works for Roush Racing and gets discounts from a lot of places.

Billy

Re: Kubota B21 backhoe axle bearings

Fri Apr 22, 2011 7:10 am

Billy, that is an unusual fail mode, for a bearing, but I have seen it before. In my case, it was a new bearing that I installed during a transmission rebuild. The bearing race split, for no obvious reason, the day after the vehicle was returned to the owner. the supplier replaced the bearing, but I had to eat the labor.
I agree that there is nothing special about that bearing and any good supply house will be able to fix you up with a replacement. All bearings & seals I've encountered on Kubota stuff has been ordinary, off the shelf, stuff.

Re: Kubota B21 backhoe axle bearings

Fri Apr 22, 2011 8:52 am

Thanks Gary

Its good to hear its most likely a std part. I am quite sure it was broke from abuse. The axles are stub shafts with about 8" between the bearings. If as my other Uncle said the kid was jumping it through the dead furrows and launching it a foot or so in the air thats a lot of abnormal stress on the bearings with the weight of the backhoe on it. It also broke the C clip on the back that holds the axle in.

Billy