Kubota front drive shaft oil seals

[eddieirvine]

I have an L3940 Kubota front oil seals seem to be an item that several have had leaking, I did not have the time or the ability to change them myself due to age and an accident. Well I did haul it to the dealer they changed them last summer and now one is leaking quit a bit, i watched several videos and a couple had roughness or rust where the seal rides, I am thinking maybe they did not clean it up or something got stuck up in there? This tractor does not get abused at all, I use it but do not abuse it. And only have one side that leaks so Monday when i call to see when i can get it in to tell them to fix the one leaking and leave the one that is not leaking alone. My question to you guys is my thinking shouldn't these last for quite a while? or is it a design problem? To add a note i replace the utd fluid shortly after i had a leak to 80 90w. And like others have said a design problem for sure. In an application like this they should have used Timken roller bearings

 

[JWR]

Quick answer is YES, absolutely. These seals should normally last the life of the machine. Can't say what the dealer did on yours but he needs to re-do it and make it right. Fairly unlikely that enough damage was ever done to the surface where the seal seats to keep it from working properly. If he claims that, make him show you. Most likely getting a new seal in there correctly will fix the issue.

 

[eddieirvine]

Quick answer is YES, absolutely. These seals should normally last the life of the machine. Can't say what the dealer did on yours but he needs to re-do it and make it right. Fairly unlikely that enough damage was ever done to the surface where the seal seats to keep it from working properly. If he claims that, make him show you. Most likely getting a new seal in there correctly will fix the issue.

I agree something they did wrong maybe not get the seal seated properly in the shoulder i don't know Monday 3/7 22 they get a call and this time they can come get it no charge imo

 

[5030]

What lubricant do you have in the outboards?

 

[Hay Dude]

I have an L3940 Kubota front oil seals seem to be an item that several have had leaking, I did not have the time or the ability to change them myself due to age and an accident. Well I did haul it to the dealer they changed them last summer and now one is leaking quit a bit, i watched several videos and a couple had roughness or rust where the seal rides, I am thinking maybe they did not clean it up or something got stuck up in there? This tractor does not get abused at all, I use it but do not abuse it. And only have one side that leaks so Monday when i call to see when i can get it in to tell them to fix the one leaking and leave the one that is not leaking alone. My question to you guys is my thinking shouldn't these last for quite a while? or is it a design problem?

I believe it is a design issue.
If you use loader to its full capability long term, or occasionally overuse, the seals will fail and possibly the bearings. I have replaced 3 in about 10 years of real farming usage (Lifting heavy bales and other heavy loader work).
The first time I replaced them, my Kubota dealer parts department gave me new bearings and seals and commented that they were improved replacement parts due to numerous failures.
I also think running the super UDT fluid in axle components is not advisable. I would run the 80-90W axle oil instead. The UDT2 is very watery and makes its way past leaking seals more easily than 80-90W. Once you get a drip, switch and it will buy you some time. It’s not a difficult job. Did my last few myself.

 

[Complete Turf Care]

I’ve had seals and bearing fail 3 times on my L5740. Here is a link to my thread on this issue over the last 6 years. Your issue may be similar.

Front wheel bearings failed L5740

Yesterday, I was loading sod with my front end loader and I could hear and feel a chatter. Suddenly, it got a lot worse and the left front wheel locked up. It would not roll at all. When I looked at it, oil was pouring out. Turns out the bearing failed. It must have been bad for a while...

www.tractorbynet.com

 

[5030]

I believe it is a design issue.
If you use loader to its full capability long term, or occasionally overuse, the seals will fail and possibly the bearings. I have replaced 3 in about 10 years of real farming usage (Lifting heavy bales and other heavy loader work).
The first time I replaced them, my Kubota dealer parts department gave me new bearings and seals and commented that they were improved replacement parts due to numerous failures.
I also think running the super UDT fluid in axle components is not advisable. I would run the 80-90W axle oil instead. The UDT2 is very watery and makes its way past leaking seals more easily than 80-90W. Once you get a drip, switch and it will buy you some time. It’s not a difficult job. Did my last few myself.

For once an informative post free of nasty comments, how refreshing.

It is a design issue. Kubota uses ball bearings in the outboards instead of roller bearings so the contact patch is much smaller, consequently, the imposed loading is much higher, been that way for a long, long time. What they should do is redesign the outboards and install angular contact roller bearings. Keep in mind they aren't the only ones using ball bearings.

You really cannot refit with rollers because the space machined in the castings for the races are too narrow.

Like you, I run gear oil in the front but unlike you, I run 85-140 Spirax. UDT and SUDT lacks the viscosity to properly shield the contact patch of the ball bearings so they fail, especially in situations where the loading is extreme (as in moving heavy loads with the FEL like for instance round bales).

The first thing I did when I bought mine new was drain out the factory fill and replace it with 85-140.

Far as the radial seal is concerned, I've never had a weep issue on either one but I attribute that to the gear oil being way more viscous than the thin liquid the SUDT-UDT is.

Until Kubota redesigns the outboards to accept angular contact rollers, the problem will persist.

The larger the tractor is, the more pronounced the issue becomes. Along those lines, I also change my front axle lubricant every year just to insure there is no breakdown in the lubricant.

 

[5030]

Like Hay Dude, I service my own. Seal and bearing replacement isn't a difficult job at all. The one thing I cannot emphasise more is, the sealing surface on the radial seal (Kubota refers to it as the ' hermetically sealed outboard is, it must be clean and corrosion free in the seal seating area as well as between the upper and lower contact area. If it's not squeaky clean when it's reassembled, chance are, it will leak. The seal depends on clean and unfettered contact.

The other thing to take note of is.. If there is any perceptible vertical movement in the outboard ( lift the wheel and axle off the ground and grasp the wheel at the top and bottom and physically attempt to move it), if there is movement, that means the bushings or the kingpin is worn and must be replaced. Once there is vertical movement, your seal's life is very finite. Not a difficult job either and I've replaced a couple bushing sets. It's usually the bushings that wear, not upper or lower kingpin. All it takes is a suitable bushing driver and a replacement set of bushings.

Horizontal movement in the wheel indicates worn tie rod ends or radial joint wear but usually the Kubota non greaseable tie rod ends are worn. I've replaced a few of them as well but I use aftermarket ends that ARE greaseable.

 

[eddieirvine]

What lubricant do you have in the outboards?

80 90 w i changed it when mine started leaking to thin of oil they come with new udt is not heavy enough in the first place, I know how to get to the seals but with my age and an accident i cannot do what i used to do 10 years ago

 

[eddieirvine]

Like Hay Dude, I service my own. Seal and bearing replacement isn't a difficult job at all. The one thing I cannot emphasise more is, the sealing surface on the radial seal (Kubota refers to it as the ' hermetically sealed outboard is, it must be clean and corrosion free in the seal seating area as well as between the upper and lower contact area. If it's not squeaky clean when it's reassembled, chance are, it will leak. The seal depends on clean and unfettered contact.

The other thing to take note of is.. If there is any perceptible vertical movement in the outboard ( lift the wheel and axle off the ground and grasp the wheel at the top and bottom and physically attempt to move it), if there is movement, that means the bushings or the kingpin is worn and must be replaced. Once there is vertical movement, your seal's life is very finite. Not a difficult job either and I've replaced a couple bushing sets. It's usually the bushings that wear, not upper or lower kingpin. All it takes is a suitable bushing driver and a replacement set of bushings.

Horizontal movement in the wheel indicates worn tie rod ends or radial joint wear but usually the Kubota non greaseable tie rod ends are worn. I've replaced a few of them as well but I use aftermarket ends that ARE greaseable.

well at my age and accident i cannot do what i used to do i worked as a machinist maintenance for 40 years know what you are saying it kills me not to be able to fix what i did for a living any more. I tore apart million dollar printing presses and repaired them so it really pisses me off not to be able to fix what i used to do. I wish i had a younger guy that would help me i could tell him what to do while i watch and guide him.