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

 

[MarkV]

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

JayC

Wow, I just ordered the seals and one "O" ring for one front side of my B21. The total was $57.37 and included $9.87 shipping. I haven't done this before so I showed the parts schematic to a mechanic friend who didn't think it should take more than a couple of hours or be that difficult. You guys that have done this, am I missing something here. I can't believe it would be $500-600 at the dealer.

MarkV

 

[rtdiggr]

Do all 4x4 tractors have this problem, or just Kubota?

JayC[/QUOTE]


My Massey is leaking again, both sides, they were replace by the dealer[under warr] i will try to change them myself this time.
My Massey has just over 800hrs.

Shane

 

[MessickFarmEqu]

Do all 4x4 tractors have this problem, or just Kubota?

JayC

Its a common fix on all makes of tractors.

 

[MarkV]

Its a common fix on all makes of tractors.

I agree and have been happy with 1600 hours on the original seals. Is this a long hour big bill fix at your shop?

MarkV

 

[MitchG]

Hi guys I'm new here. I have a 2000 model year with the same problem. It has just under a 1000 hours. The previous owner said it begins leaking from time to time. He said he replaced the seal once and then learned all he had to do was take it out and clean it and it would stop. Well the right side is leaking pretty bad. The previous owner said you can elevate that tire (block) and run the oil to the other side as a temporary fix, but I want to take it apart and have a look at the seal. Can anyone explain what is involved in taking it apart to get at the seal?
Thanks,
Mitch

 

[Jay4200]

I haven't done it myself yet, but - there is a plug that you have to pop out on the bottom of the hub, then the assembly is held together by a few big snap-rings. Download a parts manual - the exploded diagram will show you what it inside the hub/bezel. If you are going to take it apart, I'd suggest going ahead and changing the leaky seals - why not? The seals are about $50 each for my tractor. While apart, check the bearings carefully - a loose bearing sometimes causes that seal to fail, evidently. Apparently, the key to the job is a 'good' pair of snap-ring pliers, but I haven't been able to find out exactly what size or style is needed.

Dirt catches on the top of the hub and grinds into the seal - crappy design if you ask me. Sometimes, a particle of dirt will lodge under the seal lip causing a leak, but washing the area will blow the particle out and will stop the leak. My tractor has had leaky bezel seals since I got it 5 years ago, but I was always able to wash the area and slow the leaking to a manageable level - only lost about 1/2 gallon in 4 years. The starboard side seal is dry as a bone now, but toward the end of summer, the port side starting leaking like a sieve. My front axle was almost a gallon low when I filled up with the heavy stuff last month.

I put 85W140 gear oil (its like honey) into my front axle to slow it down until I get a chance to tear it apart. I don't think it made a whole lot of difference compared to the 80W90 I had in there previously, unfortunately - which makes sense since it's 80W vs 85W, although it sure looked thicker and barely flowed. I'll probably wait until spring to change the seal - it's already too danged cold to do that kind of job unless it is an emergency. My tractor seems to be leaking about 10-12oz. per month now - I'm catching it in a cup to keep an eye on it (tempted to dump it right back in too...). If it stays leaking at this rate, I'll probably only have to add oil once during the winter.

JayC

 

[Jay4200]

I just found this - might be some help:

JayC

 

[MitchG]

Thanks for the info Jay.
Mitch

 

[slowzuki]

Search around there are other threads in here, I followed one to change all the bearings and seals on one side of mine.

 

[jonyyuma]

I haven't noticed, since i just bought it, But can you access this seal with a round bottle brush to help keep mud off the seals, while washing? My Axle says L2250 on it. jy.