How bad/critical are these leaks? Kubota B3200

[Forest_Man]

I am trying to gauge and better understand what is acceptable leakage from critical leaks. And also how complicated are these repairs and whether some of the repair I should be able to do it myself. This is for a 2011 Kubota B3200 with about 900 hours.

I noticed the back of the right hand side wheel is wet with oil:

The opposite wheel not so much:

And I also noticed a oil spot right beneath the rear case, right hand side. Here are some different photos of the same oil spot:

 

[RandyT]

The first leak is not a bad repair. Remove the wheel, remove the tie rod, and unbolt the housing from the axle tube. Then put it on the bench so you can work on it. Remove the bolts holding the lower cover on the axle pivot and pry it off since it is sealed with RTV. The remove the large snap ring from the end of the tube so you can slide the upper part out of the bearings and access the seal in the lower housing. Replace the seal and reassemble.

The axle repair is more complicated since it will require removing the axle final drive from the side of the transmission. That housing also included the brake parts. along with shafts that go into the differential than may also slide out when the axle housing is pulled.

 

[rScotty]

IMHO, both of those leaks are similar because they are where axles exit an unpressurized reservoir.
If everything is right that usually means worn seals.

But first check that it the oil level is being checked with the dipstick plugged in and not overfull. Make sure the viscosity and type of oil is right - and that the vents are working properly. Both reservoirs need to have their vents working.

 

[Forest_Man]

The first leak is not a bad repair. Remove the wheel, remove the tie rod, and unbolt the housing from the axle tube. Then put it on the bench so you can work on it. Remove the bolts holding the lower cover on the axle pivot and pry it off since it is sealed with RTV. The remove the large snap ring from the end of the tube so you can slide the upper part out of the bearings and access the seal in the lower housing. Replace the seal and reassemble.

Thank you. Which parts should I buy in advance to this work? Is it just one seal? Or more parts? And are these parts something I should be able to pick up on Messicks?

The axle repair is more complicated since it will require removing the axle final drive from the side of the transmission. That housing also included the brake parts. along with shafts that go into the differential than may also slide out when the axle housing is pulled.

Okay.. this one I think I'll let the dealer deal with it...

 

[Forest_Man]

IMHO, both of those leaks are similar because they are where axles exit an unpressurized reservoir.
If everything is right that usually means worn seals.

Got it! Thank you!

Make sure the viscosity and type of oil is right - and that the vents are working properly. Both reservoirs need to have their vents working.

The operator manual doesn't mention these vents. How do I locate and inspect them?

 

[Forest_Man]

Is #150 the vent for the front case?

 

[Forest_Man]

And are these the seal(s) for the front wheel?

 

[rScotty]

Got it! Thank you!


The operator manual doesn't mention these vents. How do I locate and inspect them?

Yes, it's a good idea to see if you need seals. I'll get to vents last.... or just jump down there.

Your original question caught my interest because I've done a lot of this kind of work, and your original question was "acceptable leakage" and what is "critical"? Lotsn of leaks are in the acceptable range.
I'd say those photos show leaks that are annoying but not critical, they are minor -especially if they can be reduced a little. A little leakage is just not all that rare. If it were mine, I'd try to slow them to something that is reasonable, and then just accept it. Seals do tend to get old and leak....but there are tricks to help.

Reducing the leak starts withgetting the level right with the correct oil and making sure the vents are clear. If you are willing to check and fill occassionally, a minor leak like you are showing could be controllable for years.

Lets take the oil level first... Having too much oil is culprit #1.
Have you checked it with the dipstick for front axle and transmission screwed in? The oil level is designed to be at the bottom of the sealing surface on most rotating shaft designs. If higher, any normal seal will leak some. BTW, there are special multiple-lip seals for submerged shafts, but your Kubota doesn't have them. So check the level.

Next is the oil itself. There is often an option on oil for the front axle. Check your manual to see if there is a range of viscosity of oil allowed in that front axle. If so, it becomes your choice whether to use a low viscosity trans/hydraulic oil or SAE 80/90 gear oil.
Switching to the SAE 80/90 gear oil will dramatically slow any leak in the front axle.

For the rear of the tractor, you don't get much choice of type of oil because the hydraulic fluid and transmission oil share a common sump. So you absolutely have to use a dual purpose Trans/Hydraulic oil . Some favorites are Kubota UDT or John Deere HyGard or New Holland Multi G. Whatever you have, check that it is clear and not milky. Then check the level cold with the dip stick screwed in, not resting on the top of the case.

VENTS: I don't know where they are on your tractor. And I doubt the manual says. Often the trans/hydraulic sump vent is a little tube on a fittng under the seat. Look on top of the rear housing under and behind the seat. Look especially at the highest point of the housing.
Also, the front axle should also have a similar some sort of tube or opening - but not all did. Kubota didn't always remember front axle vents, and so some owners would add a vent to the front axle filler cap.

Basic engineering says that reservoirs have to have small open vents to deal with temperature changes in air pressure. But on tractors especially you find that some little bee or wasp has plugged those vent tubes with mud. Clean them out and stick a twist of metal screen into the tube. That will work.

Blowing into the filler hole might reveal the location of a hidden vent. I wouldn't use compressed air - that much pressure could destroy good axle seals.

Good luck,
rScotty

 

[Forest_Man]

Your original question caught my interest because I've done a lot of this kind of work, and your original question was "acceptable leakage" and what is "critical"? Lotsn of leaks are in the acceptable range.

I had the suspicion that was the case, thanks for providing the feedback.

I'd say those photos show leaks that are annoying but not critical, they are minor -especially if they can be reduced a little. A little leakage is just not all that rare. If it were mine, I'd try to slow them to something that is reasonable, and then just accept it. Seals do tend to get old and leak....but there are tricks to help.

Reducing the leak starts withgetting the level right with the correct oil and making sure the vents are clear. If you are willing to check and fill occassionally, a minor leak like you are showing could be controllable for years.

Very clear and informative, thank you again.

Lets take the oil level first... Having too much oil is culprit #1.
Have you checked it with the dipstick for front axle and transmission screwed in?

Okay, silly question: are these like car engine oil that you should let it run to operational temperature then check oil level? Is there a preferred procedure to check this and the rear case oil level?

With the tractor cold and level, I measured 3/4 full on the rear case (dipstick under the seat) and for the front case 1-1/4 full. See photos.

The oil level is designed to be at the bottom of the sealing surface on most rotating shaft designs. If higher, any normal seal will leak some. BTW, there are special multiple-lip seals for submerged shafts, but your Kubota doesn't have them. So check the level.

Yes, this seems to be the case. Do I just let it leak back to normal level then? Or should I remove it? Is it possible to drain the oil partially?

Next is the oil itself. There is often an option on oil for the front axle. Check your manual to see if there is a range of viscosity of oil allowed in that front axle. If so, it becomes your choice whether to use a low viscosity trans/hydraulic oil or SAE 80/90 gear oil.
Switching to the SAE 80/90 gear oil will dramatically slow any leak in the front axle.

Yep, absolutely correct:

I guess I know the next steps here: changing the oil and adding correct amount. Maybe wash the wheel hub so that I can better understand if leak eventually stopped.

Then check the level cold with the dip stick screwed in, not resting on the top of the case.

Not sure I fully follow you here: my dipstick is under the seat, very much like a gas engine oil dipstick that you pull out.

VENTS: I don't know where they are on your tractor. And I doubt the manual says. Often the trans/hydraulic sump vent is a little tube on a fittng under the seat. Look on top of the rear housing under and behind the seat. Look especially at the highest point of the housing.
Also, the front axle should also have a similar some sort of tube or opening - but not all did. Kubota didn't always remember front axle vents, and so some owners would add a vent to the front axle filler cap.

Gotta go look for those vents!

Thank you for all the help.

 

[rScotty]

Cleaning up some missed posts:

Yes, in post #6 the group 150 is the front axle vent. Nice if they have it. There should be a tube running up inside the front cowling to keep the vent out of rain and above water.

In post #7, those are the seals which seem to be leaking. There is also a seal where the stub axle sticks out to bolt the wheel onto. When that one leaks, it is more serious - partly because it is down low, but mostly because a leak there implies axle bearing wear.

I think that 3/4 fill and a change to 80/90 multiweight gear oil will slow that steering leak a lot. Draining and filling the front axle housing can take overnight. The thicker oil has to make it's way past some very small clearances. It takesn time.
You can remove extra oil with a syringe and rubber tube. Design-wise, my preference for the perfect level of oil for the front axle would be just touching then bottom of the horizontal rotating shaft that you can see through the fill hole.

"I guess I know the next steps here: changing the oil and adding correct amount. Maybe wash the wheel hub so that I can better understand if leak eventually stopped."

You got it. Fill very slowly. My guess is that that mud did you no favors.

I always check the oil cold. It's not all that critical for heat or level. I like to run at about 3/4 full on the reservoirs. There is still plenty of oil to be thrown around for lube without drowning the seals. The transmission level looks perfect. Always check level with dipstick pushed in.
luck,
rScotty