L3540 front axle case and hub bearings

[Tony H]

Just writing about a friends experience with his 2009ish L3540. 1900 hours.
It has the LA724 FEL... He has had issues with front axle bearing disintergrating. He is way up on maintenance, he uses all Kubota fluids yet he has had 3 failures with front axle bearings falling apart. Twice, a little fluid leak had us pulling the front axles of only to find balls in the bearing missing and scored up axles. The third time, the tire dropped without any warning. The inner bearing disintergrated causing the axle/hub to crack the housings. Is anyone having this issue? Does anyone drain the Case annually to let fresh fluid drain down from the axle tube? Whenever this happens, its not just Seals and bearings that have to be replaced. Its expensive parts that have been scored up before any signs of bearing failure. Not ho mention the disassembly time to thoroughly clean up the pulverized parts.

 

[number two]

Bummer!
Is he operating with heavy loads in that 724 loader?
And perhaps with no or insufficient counter weight on the 3 point hitch to remove weight from the front axle?
The LA724 is the bigger loader for that tractor,and overloading the front axle sounds real possible.
Good Luck!

 

[Tony H]

Bummer!
Is he operating with heavy loads in that 724 loader?
And perhaps with no or insufficient counter weight on the 3 point hitch to remove weight from the front axle?
The LA724 is the bigger loader for that tractor,and overloading the front axle sounds real possible.
Good Luck!

Heavy loads...yes. That would be my guess. He does move stone, dirt and compost around with only weighted tires. So, no counterbalance on rear wheels. But, our thinking is that if Kubota puts that FEL on that tractor....the tractor, as a stand alone, should be able to handle it.
Last Fall we did make a counterbalance. About 600lbs. Hopefully the future will not see more front end issues.
Bearings are cheap (now that we got the generic part numbers) but the ruined casting and axle parts hurt the wallet when you gotta pay Kubota prices. At least, between the two of us, we can do the work ourselves.

 

[grsthegreat]

Counterbalance is king. I built a 1000# one for mine. The first wrecked housing made me a believer

 

[bdhsfz6]

I haven't had this problem personally, but I've heard of the issue. As a result, I started using high quality 80/90 gear oil in the axle housing. I've read the specs, and people swear by the recommended Kubota SUDT2 hydraulic fluid, but I just don't trust it. It's the consistency of water when hot. The higher viscosity 80/90 oil also helps prevent seal leakage.

I don't overload my FEL, I use counterweights, and I haven't jacked up the pressure to get more lift. I really don't know if the thicker oil is the reason I've had no axle problems, but IMO, it's an ounce of prevention.

 

[5030]

We had to replace a leaking outboard seal on my 2002 M9 Kubota a few months back and the outboard is very heavy as in removal is a 2 man job. The tractor has over 4500 hours on it. 2 years ago the left hand side, we replaced the king pin bushings as they were shot and the radial seals were starting to leak. The opposite side, the bushings were tight but the outboard seal was leaking. It moves and loads round bales every season and never anything weight wise on the back for a counterweight though it also runs the 8 foot shredder as well as the bat wing when required.

The bearings were all in good condition despite the hours. Kind of surprised that Kubota, at least with the bigger units, don't use radial contact roller bearings in the outboards, they are much better suited for load carrying capacity tan the ball bearings Kubota uses. If mine ever fail, I will source radial contact roller bearings to replace the ball bearings.

I always use 85-140 GL4-5 hypoid oil in the front axles on both mine, always have actually. 85-140 is much superior in shock load capability than the UDT or SUDT and shock load capability is important to me in as much as how I use them.

Be apprised that when removing the outboards, they are very heavy and cumbersome to remove and replace and the stub axles are secured with large internal spring clips and external spring clips that entail a set of heavy duty removal tools, not your run of the mill circlip removal pliers nd to that end, I bought a set of internal and external circlip removal tools (Icon) from Harbor Freight. Not cheap, 70 bucks for the pair but a requirement to remove the retaining rings plus the gearing inside the outboard's must be removed with gear pullers to access the seals themselves.

Like I stated, if I have an issue in the future, I'll source radial contact roller bearings to replace the ball bearings simply because the contact surface with the stock ball bearings is much less than with roller bearings. Don't know why Kubota uses ball bearings versus radial contact rollers for the outboards as the roller bearings are superior in every way to the ball bearings. Even if it entails some machining of the castings to accept radial rollers, we can do that here as we have the machine capability to achieve that but in my case the ball bearings were fine. No visible wear at all. It does require a press to reassemble the outboards as well and we have that here also.

Again, I feel that 85-140 gear oil is far superior to to the UDT-SUDT far as shock loading capability is concerned, so that is what I use.

The other somewhat 'odd' things at least with my M9's is, the center section of the front axle is segregated from the outboards with a seal that installs in the center section on each side, behind the removable output shaft and bevel gear that drives the outboards and interestingly, the seal is not called out in the Kubota shop manual. Has to contact my dealer and order it. If your outboards appear to be overfilled, that indicates the seal has failed in the center section axle casting and also needs replaced. I suspect all Kubota tractors with front wheel assist have that seal.

My other issue is the way Kubota vents the axle. There is only ONE vent and it's for the center section and it's kind of hidden up under the center section pivot point. I'm going to machine the top fill plugs on my outboards to accept a vent hose that will allow the outboards to 'breathe' and reduce seal failure.

 

[Chewwy]

If one is doing real heavy FEL work or majority FEL work, one would be better off using an industrial machine. FELs on farm tractors are at best a comprimise.

 

[IndyIan]

Heavy loads...yes. That would be my guess. He does move stone, dirt and compost around with only weighted tires. So, no counterbalance on rear wheels. But, our thinking is that if Kubota puts that FEL on that tractor....the tractor, as a stand alone, should be able to handle it.
Last Fall we did make a counterbalance. About 600lbs. Hopefully the future will not see more front end issues.
Bearings are cheap (now that we got the generic part numbers) but the ruined casting and axle parts hurt the wallet when you gotta pay Kubota prices. At least, between the two of us, we can do the work ourselves.

Yeah, apparently not... I don't know what it would cost to make a front axle nearly unbreakable, but no manufacturer seems to do it. I'd guess the TLB versions have a bit stronger front axles? But if you took the backhoe off, it could load up the front axle more anyways.
I think only a skidsteer is mostly unbreakable as is, but they are dang slow, use lots of fuel, are expensive, no rear pto, and really not good on the lawn...
IMO CUTs are swiss army knives, really handy compared to nothing, but not really good at anything, and you have to work to its limitations. If you're going to be dumb, then you'd better be rich or know how to fix stuff.

 

[sd455dan]

Yeah, apparently not... I don't know what it would cost to make a front axle nearly unbreakable, but no manufacturer seems to do it. I'd guess the TLB versions have a bit stronger front axles? But if you took the backhoe off, it could load up the front axle more anyways.
I think only a skidsteer is mostly unbreakable as is, but they are dang slow, use lots of fuel, are expensive, no rear pto, and really not good on the lawn...
IMO CUTs are swiss army knives, really handy compared to nothing, but not really good at anything, and you have to work to its limitations. If you're going to be dumb, then you'd better be rich or know how to fix stuff.

Keep seeing this on multiple brands, It is usually the same failure mode, and most times it seems to be from the ball bearing cages failing from the load on each ball bearing, once the cage fractures and the balls can migrate around the race it gets ugly quick.

They either need to upsize the bearing which will give more surface area for the larger ball bearings and also a larger stronger cage. Maybe if the ball bearing manufacturers offered a super cage design/ material some of this could be avoided. Or switch like some on this site have suggested a needle roller bearing design instead.

Ball bearings once set loose eat ring and pinions for lunch. This should not be as common as it is because many do keep a good sized load on the 3 point to lower the front axle loading and keep good clean oil in their front axles.

 

[Tony H]

Counterbalance is king. I built a 1000# one for mine. The first wrecked housing made me a believer

Ahhhhh, ive been asking this question since we did the first one on his tractor. Finally someone that had it happen and verifies that counter weight is the way to go. Thanks. What model tractor?
His 600lb-ish one, he says, is borderline for snow plowing. Makes the front, almost too light for turning. Ill convince him to use it in the warm weather when lifting heavy stuff.