DEF Fluid in Hydraulic fluid

[Mikestolarik]

DEF fluid was accidentally introduced into the hydraulic fluid of a SVL95-2S skid steer. It was evident buy the hydraulic fluid turning a white color. Yes, the large DEF cover is clearly marked but the external hydraulic fluid fill tube is not. The hydraulic fluid external cap has “oil” stamped on it, but cannot be seen when covered with dust and dirt. It was a mistake; I hope folks can focus on productive answers.
DEF is corrosive to the hydraulic system and seals so the DEF must be completely evacuated from the system.

I have been flushing the system with new hydraulic fluid via;
1. Completely evacuating the hydraulic oil reservoir.
2. Fill the reservoir with 7 gallons of inexpensive hydraulic fluid.
3. Then operate all hydraulics for a couple minutes.
4. Repeat the process from step 1.

I ended up using 55 gallons of new hydraulic fluid to purge the system completely.
For the folks who fortunately have to do this, does anyone know if Kubota has a “documented procedure” for evacuating the hydraulic system?
Or has anyone discovered a better method of evacuating the hydraulic system?

The simple fix to the mistake; I placed a “Hydraulic Fluid Only” sticker above the Hydraulic fluid fill cap. Cost $3.50 for 10 stickers. All machines now have sticker indicators. I wish Kubota would have thought of this.
Thanks in advanced for all productive answers.

2/19/22 Update: I ran the Skid Steer for 8 hours today mulching trees. It seemed to operate as it should. I hope my luck continues. I will continue to update this post for positive occurrences and negative occurances. Thanks

2/3/23 Update: used the Skid Steer and mulcher all year. Changed the hydraulic fluid an additional two time. Have not seen any adverse problems. Had Kubota do a pressure test on the hydraulic pump. They noted that all pressures were good, less tan 1% down from new.

Update: 9/14/23: It's been over a year and I have not had a single problem with the hydraulic system.

 

[85Hokie]

I would imagine that what you have done .......... is the best one could do!

Cannot imagine what that cost ........ 55 gallons.

Is it working as it should?

 

[North Idaho Wolfman]

Yep there is no simple or easy procedure when that happens.
Did you change out the filters when you changed Hydraulic fluid?
I would run it for about an hour, to get it hot and then change the filter again.

 

[foobert]

Your dilution strategy is one tactic.

Is it possible to disconnect the reservoir return line(s)? If so, you could fully clean and freshen the reservoir and then operate for a short duration with the return feeding into a catch while keeping the reservoir full-enough with fresh fluid. That would greatly minimize any residual trapped in the extended systems.

But, after 55 gallons of dilution effort already expended — it may be pointless.

 

[Mikestolarik]

I would imagine that what you have done .......... is the best one could do!

Cannot imagine what that cost ........ 55 gallons.

Is it working as it should?

The cost of the 55 gallons was $360, a welcomed cost over a new hydraulic pump ($10,000).
The machine was only run for a very short time; it is also is working like it should.
The hardest part was removing the hydraulic fluid from the reservoir. We ended up using a older mechanical oil pump off a car motor. We welded two barbed fittings to the pump, and connected two hoses to the barbed fittings. The we operated the pump with a 1/2” drill. It took it about three minutes to drain the 10 gallon reservoir.

 

[GreensvilleJay]

Man this is nuts... I 'thought' the caps for fluids were all different colours these dayze......
I know it took 2 days to drain most of the SAE30 oil out of a JD ride few years back, and that's with it ON the bench,various positions,spinning things every once in awhile. A WHOLE tractor would be a nightmare.
I think changing the all the 'oil' filters say at 10-20 hrs or so, might be a good investment. I assume you've 'exercised' every valve and cylinder a zillion times......

 

[ruger1980]

The best way to clean the system after an occurrence like this is to disassemble the entire hyd. system and clean. That may sound extreme but it is the only way to ensure you have removed all of the DEF from the system.
By flushing the system several times you can dilute the percentage of DEF in the system but I would expect you will see failures or shortened lifespan of components. DEF is very corrosive and will attack the ferrous, aluminum, and brass based metals in the components. Really it is your decision and a gamble you may have to take if you don't want the labor of cleaning the system.

 

[Mikestolarik]

The best way to clean the system after an occurrence like this is to disassemble the entire hyd. system and clean. That may sound extreme but it is the only way to ensure you have removed all of the DEF from the system.
By flushing the system several times you can dilute the percentage of DEF in the system but I would expect you will see failures or shortened lifespan of components. DEF is very corrosive and will attack the ferrous, aluminum, and brass based metals in the components. Really it is your decision and a gamble you may have to take if you don't want the labor of cleaning the system.

Thanks for the suggestion. If I do that, I would take it to the Kubota dealer and let them do it, reasoning that I may miss draining a spot/area and all that work would be for nothing.

 

[Mikestolarik]

The best way to clean the system after an occurrence like this is to disassemble the entire hyd. system and clean. That may sound extreme but it is the only way to ensure you have removed all of the DEF from the system.
By flushing the system several times you can dilute the percentage of DEF in the system but I would expect you will see failures or shortened lifespan of components. DEF is very corrosive and will attack the ferrous, aluminum, and brass based metals in the components. Really it is your decision and a gamble you may have to take if you don't want the labor of cleaning the system.

Thanks for your reply, I will take that into consideration.

 

[Mikestolarik]

Your dilution strategy is one tactic.

Is it possible to disconnect the reservoir return line(s)? If so, you could fully clean and freshen the reservoir and then operate for a short duration with the return feeding into a catch while keeping the reservoir full-enough with fresh fluid. That would greatly minimize any residual trapped in the extended systems.

But, after 55 gallons of dilution effort already expended — it may be pointless.

When I viewed the inside of the reservoir, there appears to be 8-10 return lines. Your suggestion is very valid if there was a single return, I’m not sure this is an option in this case. Thanks for the suggestion.

 

[GreensvilleJay]

Yeesh. DEF is mighty wicked !! Read a few random google reports...NOT something I want anywhere near my machines ! Extremely corrosive to any metals..could be a 'looks good now, destroy you later' problem. My concern would be that some of it is in some 'nook or cranny'.
Wonder if there's some kind of 'neutralizer' additive that could be used ?

 

[Mikestolarik]

Yep there is no simple or easy procedure when that happens.
Did you change out the filters when you changed Hydraulic fluid?
I would run it for about an hour, to get it hot and then change the filter again.

That’s a good idea. Thanks for the suggestion.

Yep there is no simple or easy procedure when that happens.
Did you change out the filters when you changed Hydraulic fluid?
I would run it for about an hour, to get it hot and then change the filter again.

I changed the filters. I figured I’d run it about 6-8 hr then change the reservoir (10 gal) again. Thanks

The best way to clean the system after an occurrence like this is to disassemble the entire hyd. system and clean. That may sound extreme but it is the only way to ensure you have removed all of the DEF from the system.
By flushing the system several times you can dilute the percentage of DEF in the system but I would expect you will see failures or shortened lifespan of components. DEF is very corrosive and will attack the ferrous, aluminum, and brass based metals in the components. Really it is your decision and a gamble you may have to take if you don't want the labor of cleaning the system.

I understand, although, these skid steers are a “hydraulic line” nightmare. I would have to dissemble the entire skid steer to completely evacuate the system as mentioned. Thanks for the suggestion.

 

[Mikestolarik]

Yeesh. DEF is mighty wicked !! Read a few random google reports...NOT something I want anywhere near my machines ! Extremely corrosive to any metals..could be a 'looks good now, destroy you later' problem. My concern would be that some of it is in some 'nook or cranny'.
Wonder if there's some kind of 'neutralizer' additive that could be used ?

I thought HEET might do the trick, although I could not find any studies on its possibility.

 

[North Idaho Wolfman]

Avoid any additives as they can just cause a whole different set of worries / issues!

 

[NCL4701]

I thought HEET might do the trick, although I could not find any studies on its possibility.

DEF is about 32% urea. Hard to believe you’ll find any type of treatment that will adequately address the urea component.

The water, maybe. Urea probably not…

 

[Pau7220]

1. It sucks but does happen.
2. I sincerely believe you came up with an efficient plan of attack and made it happen. Disassembly of the machine for “cleaning” would be over the top with little or no advantage. The dilution, heating up, and emulsifying along with the multiple flushes will get it to an almost immeasurable level of urea.

 

[Mikestolarik]

Yeesh. DEF is mighty wicked !! Read a few random google reports...NOT something I want anywhere near my machines ! Extremely corrosive to any metals..could be a 'looks good now, destroy you later' problem. My concern would be that some of it is in some 'nook or cranny'.
Wonder if there's some kind of 'neutralizer' additive that could be used ?

I searched but, I could not locate any references.

 

[Mikestolarik]

1. It sucks but does happen.
2. I sincerely believe you came up with an efficient plan of attack and made it happen. Disassembly of the machine for “cleaning” would be over the top with little or no advantage. The dilution, heating up, and emulsifying along with the multiple flushes will get it to an almost immeasurable level of urea.

Thanks for the measure of confidence!

 

[Mikestolarik]

DEF is about 32% urea. Hard to believe you’ll find any type of treatment that will adequately address the urea component.

The water, maybe. Urea probably not…

From what I have investigated, Urea is ammonia and carbon. I wish I was a chemist, I would probable know of any possible neutralizers. If you discover any, please come back to the post and reply. Thanks.

 

[whitetiger]

From what I have investigated, Urea is ammonia and carbon. I wish I was a chemist, I would probable know of any possible neutralizers. If you discover any, please come back to the post and reply. Thanks.

Anything that would neutralize urea would not be suitable to dump into your hydraulic system. You have flushed the system as well as is feasible, run it awhile, then change the oil and filters again.

Be thankful that you did not put fuel or hydraulic oil into the DEF tank, that's a $17,000.00 opppppppssss.