M59 front drive shaft leak.

[rScotty]

Hersheyfarm:

I have the exact symptom on my L5240. I get a couple of drips out of the clutch drain after shutting down the machine, but my driveshaft cover also has several drips and when I pulled it off to split the tractor, there was oil trapped in the cover. I do however add UDT to the front Axle. I check and top it off once a month or so.

The transmission SUDT never goes down. Others have suggested that I replace the output shaft seal while I had my machine apart, but only having 50hrs on the machine since it was done by the dealer I bought it from, I am hesitant to mess with the seals. With the fluid loss in the front axle, It is highly likely that the pinion seal is bad in the front axle. Whenever I check my front axle, a hiss of air comes out as I turn the plug out. I know it is under pressure. Maybe fabricating a vent for the fill plug is in order.

The M59s have a vented front axle. The way it works is a rubber hose leads from a fitting on the top of the axle housing up to a metal upside down "U" tube just inboard and attached to the bracket that supports the radiator overflow reservoir. On the axle, thevent is located on the op in the middle and nearly in line with the axle pivot. Putting it there keeps the rubber vent tube from flexing so much as the axle oscillates. But better check it. On mine one of the zip ties guiding the rubber vent tube was put on in such a way that it crimped the tube and made venting problematical. Still, the venting must have worked a little bit because there's no leakage out the drive seal.

Bottom line if that if your axle housing is hissing, then it's time to rig up some venting that works. All of the axles ought to have them. Maybe yours does and it's plugged or crimped.
luck, rScotty

 

[Hersheyfarm]

So I finally got some time to get this repaired. Talking with dealer he estimated over phone $1200-1500. but as soon as they saw it, it became $5000 plus parts. They have never worked on an m59 so they were shocked to see how much has to come apart. I think it's going to have to leak.

 

[Hersheyfarm]

I brought it home and took front drive shaft off to try and absolutely verify the propeller shaft is leaking and not from axle. After you take drive shaft off which is pretty easy, this collar you see in pic slides off. The other two pics are iPhone pics I took of a handheld snake camera. You are looking at the propellar shaft and the seal that is about 5" in housing.I think it's safe to say propeller seal leaks. On the positive side, I have never had to add oil because of this leak, it minor compared to the 12 gallons it feeds from.. On the last pic it is a page from service manual. It says there should have been an o-ring on end. There wasn't.

 

[Adiredneck]

The 4wd output shaft and transmission input shaft looks identical to my 5240. I did not have to remove the mid case as your instructions say. You can get to the 4wd output shaft seal with a couple of picks after you have removed the snap ring. It really wasn't too difficult when I did mine.. I consulted the mechanic at the dealer beforehand. He has done several. You'll want an extra set of hands though. You need to keep constant pressure on the shaft to make sure it doesn't slide forward after you remove the snap ring. I am told it is very difficult to reinstall it if it comes out.

I also lifted up the mid case with an engine crane so that it was tilted up in the air. We lost maybe a 1/2 gallon of fluid that way.

 

[Hersheyfarm]

The 4wd output shaft and transmission input shaft looks identical to my 5240. I did not have to remove the mid case as your instructions say. You can get to the 4wd output shaft seal with a couple of picks after you have removed the snap ring. It really wasn't too difficult when I did mine.. I consulted the mechanic at the dealer beforehand. He has done several. You'll want an extra set of hands though. You need to keep constant pressure on the shaft to make sure it doesn't slide forward after you remove the snap ring. I am told it is very difficult to reinstall it if it comes out.

I also lifted up the mid case with an engine crane so that it was tilted up in the air. We lost maybe a 1/2 gallon of fluid that way.

Does yours have a clutch housing? The seal is about 7" deep.

 

[Adiredneck]

Does yours have a clutch housing? The seal is about 7" deep.

Not sure I understand. The clutch housing stays bolted to the engine. You split the tractor between the clutch housing and the "mid case". Once they are apart, mine looks identical to the pictures from your manual.

 

[Hersheyfarm]

Not sure I understand. The clutch housing stays bolted to the engine. You split the tractor between the clutch housing and the "mid case". Once they are apart, mine looks identical to the pictures from your manual.

I was thinking you meant you didn't split the tractor and replaced seal from propeller opening. No, you don't take the mid off, just split like yours.Difference is the loader frame makes it labor intensive. That pic is from a service manual, not instructions for seal replacement.

 

[rScotty]

As an M59 owner I've been following this with great interest. Hersey, thanks for the pics and your thoughts. Mine is doing fine at 800 hours, and I'm knocking on wood. I've had other 4wd tractors with a similar leak that comes out in the weep hole for the front drive shaft cover. On those it was the seal at the front axle end rather than the transmission. But I don't use 4wd mode all that often. Just in situations where a tire begins to spin and then go back to 2WD.

I'm still bothered by the air pressure that Adiredneck saw in the front axle on his L50 series tractor. That tractor is not set up the same as an M59, but there shouldn't be any pressure in that housing in any tractor. And I'm mystified that Kubota would recommend two completely different lubes for the front axle. Their recommendation in the owner's manual is for either UDT or Super UDT or 80/90 gear oil. No preference given. Now UDT is a very light weight hydraulic oil - almost like a penetrating oil. That kind of oil is usually used for places where the rotating parts are pressure fed and move at fairly high velocity. Sealing where hydraulic oil is used is usually by a lip seal. Then in the same sentence Kubota says we can use 80/90 gear lube for the front axle ! Now as you know, 80/90 is a thick viscous oil for use in situations with high shear forces, no pressure, and low lubrication velocity.....places where there isn't a hydraulic pump to build pressure lubrication. As I see it, the front axle with its O ring seals is an 80/90 wt. gear oil situation. Two completely different lubes recommended and no preference is given for one oil over the other. It has to make you wonder.

If it were my tractor, and I saw a leak .... well, before I split the cases I'd check that the vent hose was working properly (mine was crimped shut) - and then I'd replace the front axle lube with 80/90 gear lube. Then see if the leak changes. Splitting cases makes me shudder.
just my 2 cents worth,
rScotty

 

[Hersheyfarm]

I take it to a dealer tomorrow to get fixed. One thing I noticed about kubota dealers in general... They are either part of a bigger dealership(deere or new holland) that is unaffordable, or independent at what seems to be a used implement dealer. Atleast that is my impression. Prices have varied from around 1k-1600-5000+. The bigger dealers want it left on lot with at least 2 weeks before they can get to it. So lets see where my decision of lower price and immediate attention get me. The leak has become a steady drip when it is very hot from use, mild when not hot.

 

[rScotty]

Is the front axle still hissing when the plug is removed? If the venting system is working they can't do that. And if it is holding pressure in the axle housing then seals probably aren't going to solve the problem for long.

About what kind of shop to use, my own preference is for a well equipped independent shop.

good luck, rScotty