L2900DT-GST (4wd) Chronic Hydraulic leaks - at wits end.

[Russell King]

I would fix this on your own. Drain the fluid and get the proper fluid in it. You may want to get the dealer to tell you what they are using first. They may be dying the correct fluid but it looks like ATF or some hydraulic fluid and not the UDT type fluids that are “required”.

The leaking area under the pump should be just replacing an oring. I would recommend changing the bolts and washers also just to make sure they are the correct length.

You should inspect the mounting surface on the pump and the pipe to make sure they are not damaged. Look at the pipe overall and see if you think it has been damaged by hitting something and if it is bent. You could think about replacing the pipe if it is not expensive. That is a simple joint and should be easy to seal. The fact that it is repeatedly leaking is suspicious. That may mean it is being over pressurized and you can check the pressure setting with a gauge if you are interested in checking it. The dealer could do that also if any of this is beyond your capabilities.

There is some risk in the bolt joint in stripping the threads from the pump if the bolts are overtightened. That may be the only reason for the dealer to be involved- if you can get them to admit they did it and not accuse you of doing the damage. I think the pump body is probably aluminum so easily damaged if not using the proper torque for the bolts.

 

[North Idaho Wolfman]

This is what your dealing with, should be a simple fix.

 

[Clutch]

It looks like the pump has failed again. The fluid is running from the pump with vigor.

My question now is, would you head back to Kubota a third time for this same repair, asking that it be done for free, or take it elsewhere. Alternatively, is there a more dependable pump assembly that I could replace this one with?

It's your call here, but after spending over $5000 at the dealer and they were the last ones to touch that pump, I would be inclined to have them stand behind their work and address that leak. That includes the pickup and delivery costs. It's one thing if there are other issues, but a repeated leak from the same spot that they "fixed" is a real bummer.

If they elect not to help you with it, the other posts here have outlined the o-ring you would need to replace.

 

[CPo]

I am embarassed.... After so much advice and help here, yesterday I pulled the tractor into the garage, turned on a Salamander heater, and set to work. The work was brief.

I wrapped all the hoses to the diverter valve thing under the deck of the tractor in white foam wrap. I figured that if there was red goo on the inside of the foam, I would know which line was leaking. If there was red goo on the outside, I would know that something nearby was the problem.

Then, I tightened the two bolts holding that flange (part #90 in Wolfman's post) to the bottom of the pump. They were hand tight, but I pulled a little harder to snug them up. Being aware that the pump is aluminium, I was worried about stripping out the threads, so I stopped tightening once they felt like they were giving resistance.

Started up the tractor and spent a minute staring at the foam to see if any of them started dripping, and none did. The pump also did not drip.

So I took the tractor for a spin and "cleared the driveway" in an act that can best be described as performative. Then I took a walk around, and saw no pink juice. Parked the tractor and let it idle for a while. Still no juice. Took the tractor for a spin down the road and back in high gear. No juice.

Then I got to thinking, I had worked on a warm tractor in the garage. The tech had worked on a warm tractor in a garage. Maybe the aluminium contracts when cold, and this was a dissimilar metals problem with the steel tube it mates to, so I parked the tractor overnight, and this morning I cold started it and went and scraped the neighbour's driveway before the engine warmed up. Thick, cold fluid through cold pipes could be part of the problem, right?

No leaks. Did I pay Kubota all that money to tighten 2 bolts? I mean, I have no problem paying someone for their expertise and all that, but on the callback, if that is all they did, why did I pay another $500??

So it appears that the dealership fixed the tractor, but did not torque down those 2 bolts enough to seal the o-ring. I imagine that as the tractor runs, the fluid becomes warm and thin, and was able to push around it. I am hoping that just tightening those bolts was enough of a fix to at least get me to spring.

In the spring I'll do a fluid change etc. but in the meantime, I'll just keep those bolts tight. If this backing off is chronic, then I'll try some locktite on them. If they are backing off because the aluminium is already stripped (it felt mushy when I tightened down the bolts) then I'll see about some JB Weld in there and re-tapping threads.

Thanks all for the tips, folks. The hoses that are leaky/suspect will go to a local Hydraulics guy for replacement this week. The rear seal hasn't leaked since I cleaned it yesterday, but I'll keep a watch out.

I am embarrassed that something so simple caused me such grief,. You gave me knowledge and confidence, I am grateful.

 

[Clutch]

I am embarassed.... After so much advice and help here, yesterday I pulled the tractor into the garage, turned on a Salamander heater, and set to work. The work was brief.

I wrapped all the hoses to the diverter valve thing under the deck of the tractor in white foam wrap. I figured that if there was red goo on the inside of the foam, I would know which line was leaking. If there was red goo on the outside, I would know that something nearby was the problem.

Then, I tightened the two bolts holding that flange (part #90 in Wolfman's post) to the bottom of the pump. They were hand tight, but I pulled a little harder to snug them up. Being aware that the pump is aluminium, I was worried about stripping out the threads, so I stopped tightening once they felt like they were giving resistance.

Started up the tractor and spent a minute staring at the foam to see if any of them started dripping, and none did. The pump also did not drip.

So I took the tractor for a spin and "cleared the driveway" in an act that can best be described as performative. Then I took a walk around, and saw no pink juice. Parked the tractor and let it idle for a while. Still no juice. Took the tractor for a spin down the road and back in high gear. No juice.

Then I got to thinking, I had worked on a warm tractor in the garage. The tech had worked on a warm tractor in a garage. Maybe the aluminium contracts when cold, and this was a dissimilar metals problem with the steel tube it mates to, so I parked the tractor overnight, and this morning I cold started it and went and scraped the neighbour's driveway before the engine warmed up. Thick, cold fluid through cold pipes could be part of the problem, right?

No leaks. Did I pay Kubota all that money to tighten 2 bolts? I mean, I have no problem paying someone for their expertise and all that, but on the callback, if that is all they did, why did I pay another $500??

So it appears that the dealership fixed the tractor, but did not torque down those 2 bolts enough to seal the o-ring. I imagine that as the tractor runs, the fluid becomes warm and thin, and was able to push around it. I am hoping that just tightening those bolts was enough of a fix to at least get me to spring.

In the spring I'll do a fluid change etc. but in the meantime, I'll just keep those bolts tight. If this backing off is chronic, then I'll try some locktite on them. If they are backing off because the aluminium is already stripped (it felt mushy when I tightened down the bolts) then I'll see about some JB Weld in there and re-tapping threads.

Thanks all for the tips, folks. The hoses that are leaky/suspect will go to a local Hydraulics guy for replacement this week. The rear seal hasn't leaked since I cleaned it yesterday, but I'll keep a watch out.

I am embarrassed that something so simple caused me such grief,. You gave me knowledge and confidence, I am grateful.

Never be embarrassed if it resulted in you learning something. Ask the questions and get the knowledge. That's why we are all here to have others who have gone before us help make the process less painful.

Glad it seems to have been a straight forward fix!

 

[Russell King]

Glad you got it leakage “free”.

That joint should not be affected by the cold. The bolts are steel and the pipe flange is steel, so will expand and contract at the same rate. The aluminum body will just move a little differently but the flange will remain the same tightness regardless of the temperature.

If you need to repair the threads in the aluminum it would be best to use a thread repair insert (Time-sert, Helicoil, etc). You could have that done at a machine shop if you took the pump off and took it in. They would need a day or two to get the proper inserts. The inserts are pretty easy to do yourself but you may not feel comfortable drilling into an expensive part.

 

[CPo]

Glad you got it leakage “free”.

That joint should not be affected by the cold. The bolts are steel and the pipe flange is steel, so will expand and contract at the same rate. The aluminum body will just move a little differently but the flange will remain the same tightness regardless of the temperature.

If you need to repair the threads in the aluminum it would be best to use a thread repair insert (Time-sert, Helicoil, etc). You could have that done at a machine shop if you took the pump off and took it in. They would need a day or two to get the proper inserts. The inserts are pretty easy to do yourself but you may not feel comfortable drilling into an expensive part.

I'm familiar with helicoils (although I have never actually used them) and I have a drill press. Should be do-able at home if I can get things clamped square to the holes. Good idea, and a lot easier than my drill/tap idea.

I just took the foam wrap off the hoses and all of them had some quantity of red juice. The worst hose I am having replaced, it looks cracked. The other two, I wonder if the fittings weren't crimped on tight enough, or if the quick releases are somehow not functioning properly. That all of the fittings are leaking has me suspicious of the crimps. I'm taking these hoses to a local hydraulics shop to get them re-crimped and tested.

 

[PoTreeBoy]

I'm familiar with helicoils (although I have never actually used them) and I have a drill press. Should be do-able at home if I can get things clamped square to the holes. Good idea, and a lot easier than my drill/tap idea.

I just took the foam wrap off the hoses and all of them had some quantity of red juice. The worst hose I am having replaced, it looks cracked. The other two, I wonder if the fittings weren't crimped on tight enough, or if the quick releases are somehow not functioning properly. That all of the fittings are leaking has me suspicious of the crimps. I'm taking these hoses to a local hydraulics shop to get them re-crimped and tested.

Since you're not the original owner and therefore don't know the complete history, I'd do as someone recommended earlier and check the hydraulic pressure to make sure the relief valve pressure hasn't been over-boosted.

There are o-rings on the quick connects that have been known to leak.

 

[CPo]

The saga continues...

Since putting on new hoses, there are no more leaks at the pump or the diversion valve (yet). Last night I pulled the tractor into the garage, and this morning there is a leak under the front right steering arm casting. It looks like the gasket holding the outer and inner sections of the casting together is leaking. Or maybe the casting wasn't put together tight enough. Or something.

I tried a wrench on the bolts holding it together and they are damn tight, so unlike the pump, this is not a matter of a bolt not being torqued enough. If there is a tightening pattern maybe it wasn't followed?

The dealership's work notes say they "Replaced Front Axle Swivel Seals" on both sides. Could this be related to that? I found this video online showing that job, and it looks like this seal is part of it. Should I jack up the tractor and take that arm off, look at the O-ring inside and reset it? Any other spots to start? Any other spots that are more likely to be the source of oil dripping from that seam?

Edit to add: The oil leaking out here is strong smelling, oil-coloured oil. Not the red transmission fluid that was leaking elsewhere.

 

[RCW]

The saga continues...

Since putting on new hoses, there are no more leaks at the pump or the diversion valve (yet). Last night I pulled the tractor into the garage, and this morning there is a leak under the front right steering arm casting. It looks like the gasket holding the outer and inner sections of the casting together is leaking. Or maybe the casting wasn't put together tight enough. Or something.

I tried a wrench on the bolts holding it together and they are damn tight, so unlike the pump, this is not a matter of a bolt not being torqued enough. If there is a tightening pattern maybe it wasn't followed?

The dealership's work notes say they "Replaced Front Axle Swivel Seals" on both sides. Could this be related to that? I found this video online showing that job, and it looks like this seal is part of it. Should I jack up the tractor and take that arm off, look at the O-ring inside and reset it? Any other spots to start? Any other spots that are more likely to be the source of oil dripping from that seam?

Edit to add: The oil leaking out here is strong smelling, oil-coloured oil. Not the red transmission fluid that was leaking elsewhere.

I'm not much help with the repair, but I'm guessing the front axle has gear oil (80w-90?) in it. Has a distinctive smell and is commonly used in place of Kubota UDT fluid.

 

[North Idaho Wolfman]

The is an O-ring seal in there.
Lift it pull the tire, drain the front axle.
Remove the bolts and cases (they will be heavy) replace O-ring, reassemble and refill with Premium UDT.

 

[CPo]

The is an O-ring seal in there.
Lift it pull the tire, drain the front axle.
Remove the bolts and cases (they will be heavy) replace O-ring, reassemble and refill with Premium UDT.

View attachment 149562

Thanks... That's what I was afraid you'd say.

 

[CPo]

Thanks Wolfman.

What do you think the chances are of it being part 060 in this diagram? The oil is running down the casting and it could be coming from either spot. Would you just replace both the o-ring and that seal at once?

Either way, I think I'm parking the tractor out in the yard until I get parts. This will have to be a next weekend job.

 

[PoTreeBoy]

Thanks Wolfman.

What do you think the chances are of it being part 060 in this diagram? The oil is running down the casting and it could be coming from either spot. Would you just replace both the o-ring and that seal at once?

Either way, I think I'm parking the tractor out in the yard until I get parts. This will have to be a next weekend job.

I'd degrease that whole area and determine where the leak is. Replacing part 060 is going to be considerably more involved than just replacing the o-ring. And the leak could be somewhere else, you don't want to dive in that oil but once.

 

[North Idaho Wolfman]

Thanks Wolfman.

What do you think the chances are of it being part 060 in this diagram? The oil is running down the casting and it could be coming from either spot. Would you just replace both the o-ring and that seal at once?

Either way, I think I'm parking the tractor out in the yard until I get parts. This will have to be a next weekend job.

If it were mine I would do all the seals and O-rings at once, same amount of work and it will be all new.

 

[CPo]

FYI Kubota 'oil' here in Ontario is called 'Premium UDT'..(UDT and S-UDT south of the 49th..).. $41.46 for a 5 liter jug of it (just bought 3 on Tuesday ). It's very 'clearish'...IE NO colour !

Reaching way back to this post from @GreensvilleJay - I asked the dealership what they refilled the tractor with, and they said: "Hi, fluid was premium UDT hydraulic/transmission oil"

Would you read this as "the front axle got premium UDT, and the rear fill got transmission fluid? Or would they have topped off the existing red juice (I assume it is transmission fluid) with Premium UDT? I can't see anything on the service order saying what was put in.

 

[North Idaho Wolfman]

Reaching way back to this post from @GreensvilleJay - I asked the dealership what they refilled the tractor with, and they said: "Hi, fluid was premium UDT hydraulic/transmission oil"

Would you read this as "the front axle got premium UDT, and the rear fill got transmission fluid? Or would they have topped off the existing red juice (I assume it is transmission fluid) with Premium UDT? I can't see anything on the service order saying what was put in.

You could compare the front oil and the trans oil for thickness that might givee you some clue.

Me personally, I wouldn't take the chance I would have already drained it and put new fluid and filters in it.
If they did put the wrong oil in it, it could be damaging all the seals, then you'll be in for more leak chasing than it would be worth.

 

[Clutch]

Reaching way back to this post from @GreensvilleJay - I asked the dealership what they refilled the tractor with, and they said: "Hi, fluid was premium UDT hydraulic/transmission oil"

Would you read this as "the front axle got premium UDT, and the rear fill got transmission fluid? Or would they have topped off the existing red juice (I assume it is transmission fluid) with Premium UDT? I can't see anything on the service order saying what was put in.

You could ask them if they typically add dye to the fluid when they change it. If they say no, then you might have an idea that something is not right.

I recently changed my own fluid and added some red dye to help me see it in the sight glass and for ease of tracking down what system might be dripping.

 

[RCW]

You could compare the front oil and the trans oil for thickness that might givee you some clue.

Me personally, I wouldn't take the chance I would have already drained it and put new fluid and filters in it.
If they did put the wrong oil in it, it could be damaging all the seals, then you'll be in for more leak chasing than it would be worth.

Yeah, I have to agree with Wolfman and @Russell King at post #21.

Anything leaking from the hydraulics is red. There are red dyes for hydraulic fluid (John Deere).

Doubt a dealership would add a dye like @Russell King said a while back. Better chance they threw in ATF, and/or it had ATF in it before.

That doesn't look right, and I'd be concerned.

I'd drain whatever that is in the hydraulic system ASAP. New filters too. Just to be safe.

Front axle looks like oil with an odor, and is not red. To me sounds like gear oil. Could be wrong. If you're doing that seal, that could take care of itself when you repair it. Many guys do use gear oil. Others use UDT, as many tractors came from the factory with UDT. Some say 80w-90 gear oil is less apt to leak, as it's a little more viscous than UDT/SUDT.

 

[Russell King]

Reaching way back to this post from @GreensvilleJay - I asked the dealership what they refilled the tractor with, and they said: "Hi, fluid was premium UDT hydraulic/transmission oil"

Would you read this as "the front axle got premium UDT, and the rear fill got transmission fluid? Or would they have topped off the existing red juice (I assume it is transmission fluid) with Premium UDT? I can't see anything on the service order saying what was put in.

One description of UDT fluid is “a transmission hydraulic fluid” so I assume they mean they put the Premium UDT” in the transmission. I have no clear idea what that statement means they put in the front axle but would assume that they would put the same UDT fluid in the axle if they changed it.

See these two links for fluids with a similar description for a similar use to help understand what they are trying to say:

https://www.tractorsupply.com/tsc/product/traveller-premium-tractor-hydraulic-fluid-5-gal-t806391

MAG 1® Universal Tractor Trans-Hydraulic Fluid - Mag 1

mag1.com

But I don’t think any of these are red in color without a dye added