4x4 Kubota front axle/hub design - poor?

[Jay4200]

I've always had a little spooge on the front around the front axle seal (where the hub assy pivots against the axle housing when you turn) on my 2500-hour L4200 since I got it 5 years ago. It seemed a fairly steady seep for 200ish hours, but after putting 200 hours of dirt work on the machine this summer, the mild spooging grew into an oil spot overnight, then a bigger oil spot, then a fairly wet paper-towel overnight. Now I have to start adding oil, and I gotta change that seal someday. I had a shop-manual or parts manual diagram of it once... don't remember where that went.

Anyway, it seems to be that the Kubota front axle/hub design is stupid. I looked at a buddy's brand-new B26 TLB, and the design was the same (just in miniature). Dirt collects on the top of the hub then grinds into the axle seal. That seems like a crappy design to me. If the bottom end of the axle was bigger than the hub, or the top of the hub was tapered, it wouldn't happen. Do all 4x4 tractors have this problem, or just Kubota?

JayC

 

[Thomas]

No problem here Jay,but after I am done working in dirt/mud I hose Kubota down from top to bottom.

 

[KennyV]

Hello Jay.. mine does the same... I'm tempted to run the 85w140 gear oil in the front, that should stop or slow the seep... here are the front seals... KennyV

 

[repete]

I have become a master at replacing these on my 2550. They had a design change a few years back as I recall. I do not know if it is better or not.

What I did find was that running my front wheels reversed caused a hairline crack in my housings. I believe I replaced the seals out of habit a few years back and the leak persisted. When I looked at the loading on the front pieces I observed that the when "reversing" the wheels it increased the torque placed on the axle shaft. I believe this may have contributed to the cracking as I haul a lot of weight on the bucket transfered all the way to the bevel gear cases.

Since I returned the wheels to the "inside" position I have not had a problem with the cases.

I have really used this tough little tractor a lot and hard. I just changed the oil (every 100 hours) and recorded the change a 4750 hours. I think some time ago I said I had 5000 hours but that was incorrect. About 3500 hours ago I shoved a 1/2" diameter stick through the radiator and have yet to have it leak. I Replaced the loader bucket this spring as it was bent and the front edge was peeling apart to badly be useful any more. I would be embarrassed to post a picture. It is not pretty but it sure works hard for me!

 

[arrabil]

If it makes you feel any better, that is almost the exact same design as the typical Deere axle. You can vent your axle if you like. My posts on the subject are somewhere in the JD forums.

 

[texasjohn]

I have no problems... 800+ hrs, lots of heavy FEL work done with it.

 

[EE_Bota]

I replaced those seals this past Christmas. The tractor had 800 hrs on it. I was fairly impressed with the design overall. The seals were pretty stout, etc.

I THINK that it would actually be fairly difficult to get dirt in their at sufficient pressure to make much difference to the seal because the gaps leading to the seal are rather small. It would probably be easier to get grit in that area by running through a deep mud puddle and though other wet circumstances.

I did not do a thorough job of checking for bearing wear. I spent much more time looking for cracks in the hub.

The next time I have to change seals, I will need to be much more thorough in my evaluation of bearing wear.

 

[Jay4200]

Hello Jay.. mine does the same... I'm tempted to run the 85w140 gear oil in the front, that should stop or slow the seep... here are the front seals... KennyV

I switched to 80W90 gear oil and it did seem to help for a while. Maybe I'll try 85W140 next and see how that does. Given the spots forming under the tractor, I doubt it'll cure the problem. Maybe some of that weird #00 grease would solve the problem permenantly. I put a cup under the hub when I left my place on Sunday to catch the drips, so I'll see how much actually leaks out in a week. If it is a lot, I might just take the cup and dump it right back in!

Thanks for the pics. I may hit you up for a shop manual procedure in the future .

JayC

 

[Jay4200]

I have no problems... 800+ hrs, lots of heavy FEL work done with it.

Yea, but it's still just a baby. My L has 2500+ hours.

JayC

 

[Jay4200]

Incidentally, my local Kubota dealer charges $500-$600 to change those seals. Per side.

JayC