Assessing water in hydraulic oil

[Hman0217]

Hello

After determining there was still water in the hydraulic oil last winter, I did a second flush and refilled. I just re-drained and, this time, I collected the first bit of oil that came out to assess.

The attached picture was taken 18 hours after collection. It was milky all the way through when I collected it and you can see the slight separation there.

My hope was that any water would separate out completely but I'm wondering whether complete separation can be expected

Does anybody have any tips on determining whether I've got another flush to go on this? That'll affect whether I fill it with premium Kubota fluid or another round of the cheap travelers stuff.

Thx in advance

 

[McMXi]

Hello

After determining there was still water in the hydraulic oil last winter, I did a second flush and refilled. I just re-drained and, this time, I collected the first bit of oil that came out to assess.

The attached picture was taken 18 hours after collection. It was milky all the way through when I collected it and you can see the slight separation there.

My hope was that any water would separate out completely but I'm wondering whether complete separation can be expected

Does anybody have any tips on determining whether I've got another flush to go on this? That'll affect whether I fill it with premium Kubota fluid or another round of the cheap travelers stuff.

Thx in advance

How did water get into the hydraulic oil in the first place? Have you addressed this? Given the cost of these tractors and parts, not to mention shop rates, I'd be overly cautious and would want to have a high confidence level that the hydraulic system doesn't have water in it.

 

[Hman0217]

How did water get into the hydraulic oil in the first place? Have you addressed this? Given the cost of these tractors and parts, not to mention shop rates, I'd be overly cautious and would want to have a high confidence level that the hydraulic system doesn't have water in it.

Operator error. I had a pail of hydraulic fluid that was "sealed" but sitting outdoors for good stretch. You can fill in the blanks...

I have drained it twice now. So I don't know whether there is anything else going on. It's a 2021 l3901 stored in a soft shed. I wouldn't expect There to be additional leaks on such a young tractor so I'm assuming it's just taking me multiple passes to purge it all out.

 

[TheOldHokie]

Operator error. I had a pail of hydraulic fluid that was "sealed" but sitting outdoors for good stretch. You can fill in the blanks...

I have drained it twice now. So I don't know whether there is anything else going on. It's a 2021 l3901 stored in a soft shed. I wouldn't expect There to be additional leaks on such a young tractor so I'm assuming it's just taking me multiple passes to purge it all out.

There should be no water in a sealed pail of hydraulic oil. Your water intrusion is coming from some other source.

Flush until its gone.

Dan

 

[Hman0217]

There should be no water in a sealed pail of hydraulic oil. Your water intrusion is coming from some other source.

Flush until its gone.

Dan

Hi Dan

Let me clarify. By sealed, I mean cap in place but it had previously been opened. I KNOW it's where the water came from because I remember thinking how thin it looked when I was adding it and then all of a sudden it thickened. Oh $##!... I drained it that same day.

I really do want to focus on assessing the health of the fluid that just got drained. Respectfully, let's save the root cause analysis for now as I've gone through it.

 

[McMXi]

Operator error. I had a pail of hydraulic fluid that was "sealed" but sitting outdoors for good stretch. You can fill in the blanks...

I have drained it twice now. So I don't know whether there is anything else going on. It's a 2021 l3901 stored in a soft shed. I wouldn't expect There to be additional leaks on such a young tractor so I'm assuming it's just taking me multiple passes to purge it all out.

When you remove the transmission oil drain plugs (my MX has three) and drain the oil, and also replace the hydraulic oil filters, there's still oil in various parts of the tractor. Perhaps @whitetiger can provide some input on how a dealership would approach this problem. It's a certainty that Kubota dealers have faced a contaminated hydraulic oil system and have had to remedy the situation.

In my head, I would imagine a system that supplies clean, fresh oil to a tractor as all of the hydraulics are repeatedly cycled with no oil returning to the tank but rather to another location to be processed. Once good, clean oil is exiting the system you're done. The question is how would one do that in the real world without some expensive equipment, not to mention the cost of the oil?

Perhaps the only practical solution is to drain the system and replace filters until you're reasonably confident that the hydraulic oil is as clean and water free as it needs to be.

 

[chim]

Sounds like a meck of a hess. I really doubt that settling out can be the solution because the oil is in lots of places other then the sump. Any hose or cylinder is also storing contaminated oil. Unless someone knows of a filter that could filter the water out, getting everything empty is the only way I can think of to deal with it.

 

[Hman0217]

When you remove the transmission oil drain plugs (my MX has three) and drain the oil, and also replace the hydraulic oil filters, there's still oil in various parts of the tractor. Perhaps @whitetiger can provide some input on how a dealership would approach this problem.

Thanks. I've certainly been told this before and It's clear that I hadn't removed it all as of last winter when the hydraulic system stopped functioning properly at 11 degrees. And I welcome any mechanic's input on how to get it all. (if theres any avenues available beyond drainign plugs and filters)

I also understand that the kubota fluid can hold 1% of it's weight in water so my hope is that the last little bit is also captured that way.

But let's say you did everything right and are in a purge-until-its-gone-mode. How do you know when you're done by looking at the oil like this? Or whatever measures can you look at if there is any? I don't want to call it good and have another freeze incident this year.

So I really don't want to lose sight of this question as threads so often go on irreversible tangents.

Thanks

 

[Hman0217]

Sounds like a meck of a hess. I really doubt that settling out can be the solution because the oil is in lots of places other then the sump. Any hose or cylinder is also storing contaminated oil. Unless someone knows of a filter that could filter the water out, getting everything empty is the only way I can think of to deal with it.

True. But when you drain and add new fluid, you are diluting the water. Because that new fluid goes into all the nooks and crannies and mixes with the existing fluid. And the final 1% can be captured by the fact that the UDT2 fluid holds 1% of its weight in water. so if I know I'm at 99% fluid, I can go ahead and add the UDT2

Please do counter my reasoning if you see fit. I'm no expert but I'm just trying to think through this logically

 

[TheOldHokie]

Thanks. I've certainly been told this before and It's clear that I hadn't removed it all as of last winter when the hydraulic system stopped functioning properly at 11 degrees. And I welcome any mechanic's input on how to get it all. (if theres any avenues available beyond drainign plugs and filters)

I also understand that the kubota fluid can hold 1% of it's weight in water so my hope is that the last little bit is also captured that way.

But let's say you did everything right and are in a purge-until-its-gone-mode. How do you know when you're done by looking at the oil like this? Or whatever measures can you look at if there is any? I don't want to call it good and have another freeze incident this year.

So I really don't want to lose sight of this question as threads so often go on irreversible tangents.

Thanks

If its milky or cloudy its contamibated. Clear is good to go.

Dan

 

[McMXi]

But let's say you did everything right and are in a purge-until-its-gone-mode. How do you know when you're done by looking at the oil like this? Or whatever measures can you look at if there is any? I don't want to call it good and have another freeze incident this year.

So I really don't want to lose sight of this question as threads so often go on irreversible tangents.

Thanks

Can you send the hydraulic oil out for analysis. Blackstone Labs or similar? It's not prohibitively expensive but you'll need to find a facility who can measure the water content. I'd send a new sample of UDT2 along with a sample you collect. If you've kept oil from the first oil change you could include that too.

Blackstone does do water analysis via flashpoint but you'd need to reach out to them to see if hydraulic oil can be tested.

Standard Oil Testing | Blackstone Laboratories

Our standard analysis is all most people need. It looks at wear metals, additives, fuel, antifreeze, solids, viscosity, and air & oil filtration. Kits are free!

www.blackstone-labs.com

 

[Russell King]

To comment on a few of your topics:
1) Most tractor fluids will have emulsifiers in them that hold the water fairly well. So it will separate out eventually but could be some time.
2) Even when you drain the fluid there will be some left in the tractor (pumps, cylinders,…) but generally not enough to be a problem with contamination to the degree in that bottle.
3) You say you have flushed it twice now but not for how long the fluid is in the tractor on the first flush. That is really not that big of a deal though. You say the second flush has been in there several months (and that is the sample in the bottle.

I see that your tractor is HST and you are in the northern part of the country where it gets cold. If it was me in your situation here is what I would do. Invest in another fill of cheaper oil, run that for a week or so using the tractor as much as possible. Then run the tractor through some work for a few hours getting all cylinders activated several times each (including the three point hitch and the back hoe) to get the oil/water as mixed as possible. Then while still warm drain the cheap fluid and then refill with the SUDT2 (synthetic and costly). Change all (2?) hydraulic filters and run it through the winter. Then see what it looks like in the spring to see if you think it is still getting contaminated.

 

[chim]

This is uncharted territory for me. Other than milky-looking 90 weight in a bush hog, I've no experience. 1911's suggestion of testing sounds good.

"UDT2 fluid holds 1% of its weight in water" Is that a permissible level? Expected level from the humidity in the air? Not sure what that represents. When the oil heats up will it cause the moisture to be driven out?

 

[TheOldHokie]

[

This is uncharted territory for me. Other than milky-looking 90 weight in a bush hog, I've no experience. 1911's suggestion of testing sounds good.

"UDT2 fluid holds 1% of its weight in water" Is that a permissible level? Expected level from the humidity in the air? Not sure what that represents. When the oil heats up will it cause the moisture to be driven out?

That is a performance requirement targeting stabilithy of the formulation in the presence of water.

Virgin oil is bench tested by mixing 1% by volume of water with the oil, agitationg it, allowing it to stand, agitating again. and filtering it to collect any solids or emulsifcation suspended in the mixture. The collected contaminants are weighed and must be less than the allowable limit. The presence of free water is automatic faiilure.

A second test involves a SAE brake friction test rig and SUDT mixed with 2% by volume water. The friction characteristics of the contaminated oil must not differ from virgin oil by a srt amount.

The main concerns with water are rust and corrosion, clogged filters and valves, brake and clutch chatter, and loss of lubricity.

Ideally you want oil to be free of water in all forms - dissolved, emulsufied, and free. Dissolved water is the least concerning with emulsified and free in order being of increasing concern.

Dissolved water does not alter the appearance of the oil but micro-suspensions, emulsions and free water can be seen. If you can't see any contamination its generally fine. Visible cloudiness, emulsuons, or free water are not.

A Karl Fischer titration or water crackle lab test is overkill.

Dan

 

[McMXi]

@Hman0217, Blackstone has an à la carte menu for the tests they offer. Only you can decide what you're comfortable with in terms of confidence and cost.

Tests & Price List | Blackstone Laboratories

A comprehensive list of the more specialized tests we run. Any of these tests can be combined with the standard analysis. Call for more information.

www.blackstone-labs.com

UDT2 does appear to have a flashpoint consistent with the requirements of the ASTM test used by Blackstone, at least the lower limit.

Standard Test Method for Flash and Fire Points by Cleveland Open Cup Tester

Significance and Use 5.1 The flash point is one measure of the tendency of the test specimen to form a flammable mixture with air under controlled laboratory conditions. It is only one of a number of properties that should be considered in assessing the o

store.astm.org

Given the cost of UDT2 and Kubota's recommended change interval of 400 hours, I'd be interested in a test that helps determine the state of the hydraulic fluid. A $50 test to confirm that the fluid is good for another 100 hours might be well worth it. Kubota errs on the side of caution, but if the fluid is working as intended, does it need to be changed at 400 hours. Engine oil is cheap enough that I haven't sent samples out for testing in years, but this hydraulic oil is a different animal.

 

[TheOldHokie]

@Hman0217, Blackstone has an à la carte menu for the tests they offer. Only you can decide what you're comfortable with in terms of confidence and cost.

Tests & Price List | Blackstone Laboratories

A comprehensive list of the more specialized tests we run. Any of these tests can be combined with the standard analysis. Call for more information.

www.blackstone-labs.com

UDT2 does appear to have a flashpoint consistent with the requirements of the ASTM test used by Blackstone, at least the lower limit.

Standard Test Method for Flash and Fire Points by Cleveland Open Cup Tester

Significance and Use 5.1 The flash point is one measure of the tendency of the test specimen to form a flammable mixture with air under controlled laboratory conditions. It is only one of a number of properties that should be considered in assessing the o

store.astm.org

Given the cost of UDT2 and Kubota's recommended change interval of 400 hours, I'd be interested in a test that helps determine the state of the hydraulic fluid. A $50 test to confirm that the fluid is good for another 100 hours might be well worth it. Kubota errs on the side of caution, but if the fluid is working as intended, does it need to be changed at 400 hours. Engine oil is cheap enough that I haven't sent samples out for testing in years, but this hydraulic oil is a different animal.

I think that strategy requires a lot more testing than a $50 Karl Fischer titration.

Dan

 

[jspicerreachnet]

First verify the at full capacity. Do a 100% drain and determine how much is left in cylinders etc. Fill with diesel fuel, run all hydraulics 1/2 hour and drain. Repeat with second fill 50-50 diesel and hydr oil. Then conplete by filling 100% hydraulic oil. Let the 50-50 mixture settle and any water in on the bottom.

 

[McMXi]

I think that strategy requires a lot more testing than a $50 Karl Fischer titration.

Dan

No doubt. There are lots of interesting articles detailing how and why hydraulic oils fail, but it is interesting to know if Kubota's recommended intervals are necessary. How much good oil is being discarded prematurely? If you can keep contamination out of the oil, whether it's dirt or water, and change filters at the recommended intervals, perhaps the oil life can be extended.

From the article below:

"Oxidation is the major source of viscosity increase, varnish formation, sludge and sediment formation, additive depletion, base oil breakdown, filter plugging, loss of foam resistance, loss of demulsibility, acid number increase, rust and corrosion."

The article below mentions that the reduction in volume of hydraulic systems over the years in order to reduce costs has added to the stress on the fluid.

Saying all this, I tend to hedge my bets and follow Kubota's guidelines when it comes to maintenance. I have no desire to be a $50k plus guinea pig for each tractor.

The real reasons why hydraulic fluids fail

www.stle.org

 

[Shawn T. W]

Water in a "freezable" form will probably add unhappiness if you go below freezing this winter ...

I'm not sure of the operating temperature of a hydraulic system, but know if I touch a hydraulic line fitting or cylinder while working that item, it's "hot" to my hand ... Is it hot enough to "boil it off"? If so, would the "steam" stay a gas long enough to find the vent and "escape" ...

I'm wondering ... If an item like diesel anti-gel that has a de-emulsifier in it would help separate the water from the oil? It wouldn't take much.

In the propane business we use to add methanol to it, as it has water in it as a hydrocarbon, and the methanol "dries" it ...

 

[RCW]

Water in a "freezable" form will probably add unhappiness if you go below freezing this winter ...

I'm not sure of the operating temperature of a hydraulic system, but know if I touch a hydraulic line fitting or cylinder while working that item, it's "hot" to my hand ... Is it hot enough to "boil it off"? If so, would the "steam" stay a gas long enough to find the vent and "escape" ...

I'm wondering ... If an item like diesel anti-gel that has a de-emulsifier in it would help separate the water from the oil? It wouldn't take much.

In the propane business we use to add methanol to it, as it has water in it as a hydrocarbon, and the methanol "dries" it ...

Several times I've seen citations here on OTT that a system can run ambient temperature + 100* F.

So, under certain circumstances it potentially could evaporate water, but certainly not an efficient way to do it.

I've seen recommendations to use diesel to flush a water contaminated sump. Diesel would likely mix/blend with the hydraulic fluid and can't separate again....