New(ish) Kubota M62 With Filthy Hydraulic Oil

[rScotty]

mtputney,

I'm a bit confused. I just looked at the OrangeTractorTalks thread and don't see a mention by rScotty but I do see the above thread #34 where I replied to both rScotty and yourself: "I am NOW suspecting you received an M62 that Kubota delivered without flushing or adequately flushing the hydraulic system, after assembly/ manufacturing, before delivery. you indicate you received tractor new from a dealer ( a dealer who clearly should be out of business given their refusal/ denial of a clear problem with newly delivered machine that is within warranty period)."

Good to see you are flushing the system out. I would also be contacting Kubota's regional sales rep to lodge a complaint and work to get them to pick up the costs of poorly delivered machine.

Please elaborate on "we know that the dealer didn’t do most/all of the dealer prep because of other things that got missed."

Hope you are successful.

Sometimes it's hard to know who said what to whom.... But M59 is right on that - I didn't say anything about the practice of " flushing or adequately flushing the hydraulic system"

Mainly because I don't think it is possible. How would one go about flushing the hydraulic system.
Sure, "Flushing the System" sounds good, but I'm afraid it's an impossibility.

Yes, mechanics use the slang term "flushing the hydraulic system", but stop and think about what that would entail. I'm not even sure what it means or how to go about it - and I had a repair shop for years. There are just too many paths for fluid to go down and too many places where fluid and particles can sit without circulating. To really clean a hydraulic system would take removing every hydraulic component, taking it apart, and cleaning it individually. That's what is done at the factory, but they do it BEFORE assembling all the parts together to make a tractor. Once assembled I doubt there is any way to "flush" the whole system.

Changing oil they can do for sure, but not anything that you cannot do yourself. Plus I would wonder about the wisdom of taking something back to where they got it wrong to begin with.
So "flushing" is NOT part of prepping a tractor for sale. Forget that. Changing oil might be, and some dealers will do a change when a tractor is new and then again at 50 hours if pressed. To the factory's credit, at least that 50 hour change is required in the owner's manual....that's good, but I wonder how many new owners really do it.

rScotty

 

[M59]

mtputney,

You had previously asked where the vent was for the hydraulic system. Below is picture of the back end of the M59 where you can see the 3 pt lift arms and in the center, at pic top, is a dip stick handle and a plug for filling the hydraulic reservoir. On top of the plug is a upside down "J" shaped rubber tube. This is the hydraulic system vent breather tube. It is unlikely you could spray water into the open tube due to it being flexible and upside down.

rScotty and I are going to agree to disagree on ability to flush the hydraulic system. Presuming the hydraulic reservoir contains a minimum of 70 to 90 percent of the total hydraulic fluid then changing fluid once would eliminate 70 to 90 percent of the contamination, leaving 10 to 30% in the system. Cycling the hydraulic system ( extending and retracting all the hydraulic cylinders) would distribute a portion of the remaining contaminants back to the reservoir. Dumping reservoir second time would leave 1-21% of contaminants in system. Cycle again, dump and refill leaves 0.1- 14.7% of original contaminants in system. The latter is something I could live with.

I have not looked at the Kubota Workshop Manual for M59 for the hydraulic reservoir capacity or system capacity but I presume one could find out the reservoir capacity by knowing how much hydraulic fluid is required to perform the recommended service schedule.

 

[rScotty]

mtputney,

You had previously asked where the vent was for the hydraulic system. Below is picture of the back end of the M59 where you can see the 3 pt lift arms and in the center, at pic top, is a dip stick handle and a plug for filling the hydraulic reservoir. On top of the plug is a upside down "J" shaped rubber tube. This is the hydraulic system vent breather tube. It is unlikely you could spray water into the open tube due to it being flexible and upside down.

rScotty and I are going to agree to disagree on ability to flush the hydraulic system. Presuming the hydraulic reservoir contains a minimum of 70 to 90 percent of the total hydraulic fluid then changing fluid once would eliminate 70 to 90 percent of the contamination, leaving 10 to 30% in the system. Cycling the hydraulic system ( extending and retracting all the hydraulic cylinders) would distribute a portion od the remaining contaminants back to the reservoir. Dumping reservoir second time would leave 1-21% of contaminants in system. Cycle again, dump and refill leaves 0.1- 14.7% of original contaminants in system. The latter is something I could live with.

I have not looked at the Kubota Workshop Manual for M59 for the hydraulic reservoir capacity or system capacity but I presume one could find out the reservoir capacity by knowing how much hydraulic fluid is required to perform the recommended service schedule.

What you are proposing requires that all the particles be suspended in the fluid. Of course that will work. If that were true, all one would have to do is change fluids. But if that was true it would have already worked. In fact, the filter would have already done the job. Apparently there are lots of contaminents and they are not easily suspended.

The problem with flushing any system with more than one fluid path comes down to the physics of flow. It is easiest to visualize in an open channel problem like a creek. Total flow may increase, but it becomes stratified so that there is always going to be rocks and sand on the bottom of the creek. With one single path, a flushing type of flood could sweep the channel smooth, but with more than one path, it can't. A similar thing also occurs in multiple closed channels like a hydraulic system. The problem is that as obstructions build up in a flow path, the velocity along that path decreases. The flow then chooses an alternative path and increases proportionately, leaving the old path and debris in place.
rScotty

 

[ponytug]

Thanks everyone for the excellent advice. Please excuse the delay responding – I’ve been busy changing the fluid.

Additional Information:

Tractor was purchased new from dealer– no previous owners. Unfortunately it looks like we chose a bad dealership. He is refusing to help. Called Kubota - they say its between use and the dealer.

All maintenance done at the suggested hours.

No use of hydraulically driven attachments.

We’re very careful with the cleanliness of the hydraulic connectors when taking the backhoe off/on.

Tractor get used every other day or so – always to recommended temperature.

Tractor is housed in a barn – but we do wash it frequently.

Sizzle test for water is between negative and 0.05 - 0.1% 500-1000 ppm. It was zero with Blackstone.

Again – thanks for the help.

The good news is that you have discovered a dealership to avoid. Write Kubota a letter to let them know that they have a dealer problem, and ask that Kubota make things right, at a minimum pay for your out of pocket oil and filter changes, and hopefully an extension to the warranty, but absolutely take your business elsewhere. Once you have found a dealer to be unreliable, there is no going back in my book.

If the water didn't come in through your vents, I suspect that you are right that the water got in there earlier. I do think that you are right to do a couple of fluid changes. A tip from folks who restore old tractors with water in the hydraulics; you might consider adding a few gallons of diesel in one change to help to soak up any water. Put the diesel plus oil in, run it, let it sit over night and drain. My bet is that the tractor wasn't prepped by the dealer correctly.

I agree with @rScotty and also think that the sizzle test is not relevant; it doesn't apply to modern fluids. Have you cut the used filters open and unraveled the pleats to look for debris?

I would add magnets to the outside of the filter for at least a while.

All the best,

Peter

 

[hayden]

OK, I'll ask. Who's the dealer?

 

[M59]

What you are proposing requires that all the particles be suspended in the fluid. Of course that will work. If that were true, all one would have to do is change fluids. But if that was true it would have already worked. In fact, the filter would have already done the job. Apparently there are lots of contaminents and they are not easily suspended.

The problem with flushing any system with more than one fluid path comes down to the physics of flow. It is easiest to visualize in an open channel problem like a creek. Total flow may increase, but it becomes stratified so that there is always going to be rocks and sand on the bottom of the creek. With one single path, a flushing type of flood could sweep the channel smooth, but with more than one path, it can't. A similar thing also occurs in multiple closed channels like a hydraulic system. The problem is that as obstructions build up in a flow path, the velocity along that path decreases. The flow then chooses an alternative path and increases proportionately, leaving the old path and debris in place.
rScotty

rScotty,

I am basing my response to mtputney wholly on his published test results which showed both a certain solids level and a visual turbidity within the hydraulic fluid. The test results were on on the hydraulic oil he sent in for test so "flushing" the hydraulic system would remove those solids indicated in the test results and were evident in the visual turbidity. If there are other unknown solids in the system that were not present in mtputney's sample sent in for test and not included in the test results then mtputney has a bigger unknown problem. Filters have a cut off point where they are incapable of removing solids below a certain micron size ( I do not know what that size is for the filter on mtputney's M62 ) OR the filter is clogged/ loaded up and the bypass valve is allowing the solids to bypass the filter. Only a filter examination and review of the filters specs would answer this point.

As to the flow physics. Kubota hydraulic HST systems, present on M62, are separated into three flow streams. One pump dedicated to steering and driving the wheels. I do not know how Kubota manages the pressure and flow volume management for steering/ driven wheels but it uses hydraulic fluid from the common hydraulic reservoir. The second pump supplies hydraulic fluid to the FEL and three point hitch. The third pump powers the backhoe. Unless one has ate extreme dexterity, which I do not have, I find it unreasonable that both the FEL and backhoe can be operated at the same time so the multiple path problem goes away.

The pumps are running at all times and pumping fluid thru the open centers of all the valves so the fluid is constantly being cycled from the common reservoir, out to the valve, and then back to the common reservoir at effectively zero pressure since no work is being asked of the pumps. Only when the operator changes the valve position does the pump see a request for work and the pressure that the pump is capable of builds up and the cylinder extends or compresses. If there was an alternate path for the hydraulic fluid then the fluid would choose the path of lowest resistance and the operator's change to the valve position would produce little or no work.

Operating each valve, on at a time, will cause the fluid in each circuit to flow from the pump, thru the valve, out to the cylinder, and then back to the reservoir. The multi parallel resister network does not apply when each valve is operated one at a time.

If a particular circuit has a buildup of "sludge" then the circuit will develop full pressure but the cylinder will operate at a noticeably slower rate because the volume flow thru the circuit is being reduced by the obstruction.

 

[mtputney]

UPDATE

I’m not gonna say this is the most fun we’ve ever had with a new tractor.

To review:

We noticed at about 200 hours that the hydraulic oil on our new M62 looked less translucent than we were used to - did an oil change and it looked pretty awful (see previous pictures).

Sent it off for analysis (see attached) September of 2022 and it came back with the insoluble’s four times over the upper limit.

Kubota helpline was completely not helpful. Out-of-state dealer that we purchased it from also not helpful.

Did two complete changes of the hydraulic oil and filters ($600) and then sent the tractor to the nearby dealer for an “hydraulic washout” - $600 transport fee - when the tractor got to the dealer we found out that the washout would not be covered under warranty and would cost thousands of dollars.

Regional representative told dealer that this is normal for the hydraulic fluid in a new Kubota tractor.

Paid for another complete hydraulic oil and filter exchange. Now insoluble’s are just slightly above the recommended limit (see attached).

Blackstone is recommending another change of the hydraulic oil filters.

Questions?

Has anyone had a similar experience?

Any idea what’s going on - is this normal?

Should we change the hydraulic filters again?

Should we change the hydraulic oil again?



Thanks in advance for any advice.

 

[BeezFun]

Blackstone is recommending another change of the hydraulic oil filters.

Usually there is a narrative with the Blackstone result that gives an explanation for things that are out of range. When your insolubles were way high last year, did Blackstone give any explanation of what might cause that?

 

[rScotty]

UPDATE

I’m not gonna say this is the most fun we’ve ever had with a new tractor.

To review:

We noticed at about 200 hours that the hydraulic oil on our new M62 looked less translucent than we were used to - did an oil change and it looked pretty awful (see previous pictures).

Sent it off for analysis (see attached) September of 2022 and it came back with the insoluble’s four times over the upper limit.

Kubota helpline was completely not helpful. Out-of-state dealer that we purchased it from also not helpful.

Did two complete changes of the hydraulic oil and filters ($600) and then sent the tractor to the nearby dealer for an “hydraulic washout” - $600 transport fee - when the tractor got to the dealer we found out that the washout would not be covered under warranty and would cost thousands of dollars.

Regional representative told dealer that this is normal for the hydraulic fluid in a new Kubota tractor.

Paid for another complete hydraulic oil and filter exchange. Now insoluble’s are just slightly above the recommended limit (see attached).

Blackstone is recommending another change of the hydraulic oil filters.

Questions?

Has anyone had a similar experience?

Any idea what’s going on - is this normal?

Should we change the hydraulic filters again?

Should we change the hydraulic oil again?



Thanks in advance for any advice.

I don't see the problem. It looks to me like the change of fluid and filters did a good job.
Your original showed some sort of contamination, but apparently that has been dealt with. New tractors have a surprising amount of crud that has to be filtered out.

Nobody can evaluate the light metals below Boron that show high ppm without comparing to what is normal for that particular batch of oil. Those metals are all typical of the very high additive packages used in trans/hydraulic oil. Calcium is within 1% so no data there. The others show expected depletions. Kubota does not make their own branded UDT2 trans/hydrualic oil and they are aware that the various compounding companies they use do differ. So you need to include analysis of an unused sample of the exact container of UDT2 you put into the tractor if you want an accurate starting number for the additive chemicals.

Similar experience -well, I've not seen oil looking like that when I look at our M59 - which pretty much the same tractor but pre-tier4 emissions so we often run at high idle, not at high RPM. Because of the RPM difference I would expect that ours would have less entrained air than you show in your original photo.

I have seen similar cloudy trans/hydraulic oil in other machines. Cannot tell from your one picture last Oct. 2022 whether it was entrained air as microbubbles or actual particles or just what it is. It might even be from a small suction air leak. You might want to consider taking one photo right after warm sample is in the mason jar, and then again two days later after the mason jar sits quietly. Then again at a month.
To my eye, what I am seeing looks like as much air as anything else. Especially if that is a fresh sample. Let it set a few days and air will make it's way to the top and escape. Solid particles - even micro particles - will settle to the bottom in about a month. Water should stratify by then as well - although t the report doesn't show water. I don't know what water test Blackstone uses, but the the water test one used by many oil analysis companies was not very accurate.

Is there some particular thing that you don't like about the oil report?

At this point & given the oil report i would consider changing filters - simply because with that much reduction of insoluble solids the filters may be getting filled up.
The HST is the most sensitive system in the tractor & so it has a special super fine filter just for oil entering the HST. Because that is a common sump hydraulic system that HST fine filter also functions as a bypass filter to slowly super-filter all the entrained solids for all the oil. That might be an argument to replace it.
I would not change the oil unless doing so just for convenience.

Other than being worried like any new owner, how is the new tractor doing?

rScotty

 

[mtputney]

rScotty:

Please excuse the delay in responding - I truly appreciate hearing your thoughts and found them helpful and reassuring.

I guess I was mainly concerned because our previous tractors always had very clean looking hydraulic oil - so the appearance of this oil was a surprise.

As you read - I initially expected Kubota to be able to reassure me that this was normal. But unfortunately we have not been able to get any useful response from them. I specifically asked them if new tractors should have hydraulic fluid looking like this…

Just a reminder - we changed the hydraulic oil and filters three times, so I guess I was expecting the insoluble’s to drop even more.

Blackstone is simply recommending changing the filters again - which we will do.

We’re actually really pleased with the machine and its performance otherwise. We use it principally in our woodlot in Vermont and the extra reach of the oversized hoe is a big help. However, even with axle extenders we have to be a bit careful with the backhoe all the way off to the side as it tends to tip up the tractor. The only thing I would change in design would be to make larger stabilizers - similar to what we had on our Deere 110TLB.

The fit and finish on delivery was pretty disappointing - there were numerous problems like missing grease holes - and in the end the out-of-state dealership wouldn’t stand behind the machine. However, our local dealer engaged Kubota regional and made good on almost everything. For instance, they replaced the backhoe main boom because the welds were so poor. We had a new Kubota decades ago and my memory is that we had no problems whatsoever.

Again thanks a lot for your advice - I put a jar of the original dirty looking fluid into storage months ago - I’ll go find it and get back to you.

Thanks

Norman