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Quick fluid change ques.

seagull369

Active Member
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May 13, 2009
Messages
30
Location
New York
Hiya, guys. I was wondering if the position of the hydraulics has anything to do with how much fluid will come out during a change. Some water got in my hoe's system and after draining, filling and running the hydraulics through their motions twice , it's still looking like chocolate milk in there.
 

bill onthehill

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Dec 27, 2008
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pa/ny border
I would think you want as many cylinders retracted as you can to return the greatest volume of oil to the tank. you can figure 3 times to get it all out of the system.
 

surfer-joe

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Mar 25, 2007
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Location
Arizona
If a hydraulic system becomes contaminated with water or anything else, it has to be completely disassembled and ALL components drained and flushed. This means the tank, the cylinders, the valves, all hoses and tubes (all opened up, cleaned, and reassembled), and the filters and their housings of course.

This is the only way to be sure you have removed all the contaminant. Doing anything else only continues to contaminate, and wastes the new fluid you install. Just draining the tank and changing the filters only dilutes the contamination down to smaller levels every time. There will still be water left in the oil and it will do damage to your system.

Even after a complete system rebuild, the fluid and filters should be changed again after a short interval.

Fluid sampling can help determine what the water level is and you can make some decisions after knowing what that is.

Good luck!
 
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OneWelder

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Apr 12, 2007
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483
Location
Derry, New Hampshire
When I have had to deal with contaminated systems - I raised booms up drained system then tipped buckets and lowered booms
to get as much fluid out at one time as possible -you will need to do more than once- otherwise take it apart one component at a time -also I do not know what your machine is but if the trans uses a common reservoir you need to be careful
 
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RobVG

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Seattle WA
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If a hydraulic system becomes contaminated with water or anything else, it has to be completely disassembled and ALL components drained and flushed. This means the tank, the cylinders, the valves, all hoses and tubes (all opened up, cleaned, and reassembled), and the filters and their housings of course.

That's certainly true if you're working on the Space Shuttle.

But there are alternative methods of removing water from your hydraulics.
 

Tinkerer

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May 21, 2009
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10,169
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usa
Three weeks ago I had to do a complete hydraulic system oil change because of water contamination. This is how I did it. Retract all the hyd. cylinders even if you have block some components to keep them retracted. Now unhook ALL of the hoses from the ALL of the cylinders. Completely drain and clean out the hyd. tank and install a new filter. Fill the tank with clean oil. Now start the engine and flush all of the unhooked lines until you get clean oil coming out of them. Be sure to keep the oil tank full as you do this. Reconnect the lines on the retracted (closed) side of the cylinders. Now extend all cylinders slowly and completely. Be carefull because oil will be coming out of the extended side of the cylinders with a lot of force ! After extending the cylinders reconnect the the hoses to them. Now all the system should be completely flushed except the swing cylinders. I flushed the swing cylinders in the following manner. Stabilize and level the machine with the outriggers. With the boom on the ground so it cannot swing unhook all the hoses to the swing cylinders. Now flush all of the unhooked swing cylinder hoses. Next be sure no one is in the swing path of the boom. Raise the machine with the outriggers being carefull to keep it level until the boom is clear of the ground. I was now able to swing the boom in a full arc left to right by pushing it by hand. This will completely flush all the contaminated oil out of the swing cylinders. Next lower the machine so the boom is resting on the ground. This will prevent the boom from swinging as you reconnect the hoses. The boom has to be prevented from moving so you will not get caught as you reconnect the swing cylinder hoses. After completing this,the entire system will be flushed. This is what worked for me and I now have machine with oil in it that looks as clean as it did when the oil was new in the 5 gallon pails. It did require 40 gallons of new oil to accomplish the flush but that is a lot cheaper than replacing a hydraulic pump or who knows what else water contamination destroys.
 
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seagull369

Active Member
Joined
May 13, 2009
Messages
30
Location
New York
I was afraid someone was gonna say this'd be more than a simple fix :( ,,,,but thanks so much for all the great, speedy replies. I really have no one else to ask this stuff to.

My machine is a Case 580 SE, where (I believe) the transmission (hydrostatic) and all hydraulics (aside from the brakes) in the back there work off a common reservoir. Given that I'm wondering if that throws a wrench into your idea, Tinkerer. I guess that all depends on whether or not all of the fluid comes out of the hydrostat when I drain it. If doesn't, I imagine I'd just be spewing more contaminated fluid out those disconnected lines I was trying to purge.

I read your link about polymeric filters, Rob, but there was a significant amount of water that got in there (stupid me left the cap off). Because of that, a polymeric filter might not be much help. "Vacuum distillation" and "headspace dehumidification" sounds like they require special equipment I don't have and unfortunately can't a shop to do.
 

RobVG

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Seattle WA
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First off, I'm no expert. Use your own judgment.

My experience came from a Zaxis 160 when the operator called me to say the hydraulic look milky. I came out and sure enough, it looked like a butterscotch milkshake. I talked with the service manager at our local dealer and he said they had a filter that they could run it through. He also said I could change it a few times and try to drain as much out as I could. I opted for the drain/change and the machine has run without a hiccup for the past 3 years. The hydraulic is clear.

PS We have a 580 Super K- the transmission and hydraulic system are separate...pretty sure...
 
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willie59

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I agree with you RobVG. If my memory serves me correctly, the 580 Super E had a seperate hyd reservoir from the tranny reservoir.
 

seagull369

Active Member
Joined
May 13, 2009
Messages
30
Location
New York
I agree with you RobVG. If my memory serves me correctly, the 580 Super E had a seperate hyd reservoir from the tranny reservoir.

Shows you what I know. I checked my handy ebay manual and it shows a separate capacity for the power shuttle so you're right.

Tinkerer, I'll try your idea and report back. Thank you all again.
 

Tinkerer

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usa
seagull, I believe ATCOEQUIP is correct. I just took a quick look at the online parts manual for a 580SE Super. It definitely shows a separate dipstick for the transaxle housing. Also the brakes are regular ones with master cylinders. My machine was heavily contaminated with water when I bought it. But I made it worse when I too left the tank cap loose overnight while I was in the process of repacking a cylinder. Of course we received a 2" rain that night. I do not regret going through all the work and oil it took to get the system clean. If I had let the contaminated oil damage any of the system components I still would of had to flush out everything.
 

Sslane

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Joined
Mar 7, 2025
Messages
15
Location
California
Three weeks ago I had to do a complete hydraulic system oil change because of water contamination. This is how I did it. Retract all the hyd. cylinders even if you have block some components to keep them retracted. Now unhook ALL of the hoses from the ALL of the cylinders. Completely drain and clean out the hyd. tank and install a new filter. Fill the tank with clean oil. Now start the engine and flush all of the unhooked lines until you get clean oil coming out of them. Be sure to keep the oil tank full as you do this. Reconnect the lines on the retracted (closed) side of the cylinders. Now extend all cylinders slowly and completely. Be carefull because oil will be coming out of the extended side of the cylinders with a lot of force ! After extending the cylinders reconnect the the hoses to them. Now all the system should be completely flushed except the swing cylinders. I flushed the swing cylinders in the following manner. Stabilize and level the machine with the outriggers. With the boom on the ground so it cannot swing unhook all the hoses to the swing cylinders. Now flush all of the unhooked swing cylinder hoses. Next be sure no one is in the swing path of the boom. Raise the machine with the outriggers being carefull to keep it level until the boom is clear of the ground. I was now able to swing the boom in a full arc left to right by pushing it by hand. This will completely flush all the contaminated oil out of the swing cylinders. Next lower the machine so the boom is resting on the ground. This will prevent the boom from swinging as you reconnect the hoses. The boom has to be prevented from moving so you will not get caught as you reconnect the swing cylinder hoses. After completing this,the entire system will be flushed. This is what worked for me and I now have machine with oil in it that looks as clean as it did when the oil was new in the 5 gallon pails. It did require 40 gallons of new oil to accomplish the flush but that is a lot cheaper than replacing a hydraulic pump or who knows what else water contamination destroys.
Doesn’t the HYD pump constantly run? If so, wouldn’t it cycle oil in the tank as soon as it starts up and sits idle ? So won’t the new oil that’s put into the holding tanks get contaminated with the milky fluid in the bypass lines?
I need to do this flush but wondering about this.
I was thinking you could disconnect the suction line and suck from a bucket. But maybe it won’t work or this is not actually how the pump works?
 

HarleyHappy

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So NH
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Yes, the pump is constantly running and the oil cooler circulates all the time.
There was a different way to purge the hydraulic system posted on here and that is how I did mine but it requires about 30 to 40 gallons on hydraulic fluid.
I will see if I can find it and post it as it’s quite involved.
Basic process was disconnecting filter return and dumping that into a big bucket, I used a 40 gallon trash pail.
Then you start the backhoe intermittently moving certain functions as you do it and immediately shut it down. That way, you are not mixing good and bad oil.
The way I did it was the way Wille59 describes it.
Good luck.
 

B&B

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Oct 8, 2022
Messages
97
Location
Massachusetts
Hiya, guys. I was wondering if the position of the hydraulics has anything to do with how much fluid will come out during a change. Some water got in my hoe's system and after draining, filling and running the hydraulics through their motions twice , it's still looking like chocolate milk in there.
There's a product I've seen used named mechanic in a can to help take water out of hydraulics. I had a customer use too much of it and the oil got cleaner but he had the hyd filter restriction light come on so we changed fluid and filters and it's been much cleaner and fine since. 1 gallon of this stuff treats probably 40 gallons of hyd oil so it's important to use as directed.
 

92U 3406

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Western Canuckistan
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Realistically what customer is going to pay to have the entire hydraulic system disassembled for some water contamination? You can barely convince most customers to go that far when a pump or motor failure sends shrapnel through the system.
 

B&B

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Oct 8, 2022
Messages
97
Location
Massachusetts
Realistically what customer is going to pay to have the entire hydraulic system disassembled for some water contamination? You can barely convince most customers to go that far when a pump or motor failure sends shrapnel through the system.
To be fair my personal service truck has had milky hyd oil for a little too long, not enough time in the day sometimes
 

HarleyHappy

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So NH
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I looked up the product called Mechanic in a Bottle for milky or contaminated hydraulic oil.
While I had never heard of this product (Thanks B&B) I am somewhat spectical.
Watching the video, it does look promising but why isn’t everyone gleaming about it?
I am actually considering this, I still have a bit of water in my hydraulics, even after the draining and flushing procedure. Not much at all, at the moment, I think most of it is moisture, with the extreme temperature swings we have been having.
When I did my flush, I put a 3/4’ gate valve in the hydraulic tank drain.
If I don’t run it for a while, I will put a hose on the valve and drain, I generally only get a couple of ounces of water out and the hydraulic fluid is not milky at all.
Still, watching that “MAGIC” video, I have never been a fan of any additives or snake oils for over 30 years.
Still have half a case of Slick 50 after being at a demonstration in my 20’s and watching them run a B&S 3 1/2 horse engine for 20 minutes, with no oil in it, after draining the crankcase that had half a quart of Slick 50.
Then, after determining cost and such, just decided a good oil and frequent oil changes, that should be good.
This was before any synthetic oils had hit the market.
Now, if it’s a gas engine, I run Mobil 1 for cost and confidence and change every 4 to 5k on older engines.
On diesel’s, I run Rotella T4
I hate water in hydraulic oil.
 

Sslane

Member
Joined
Mar 7, 2025
Messages
15
Location
California
Yes, the pump is constantly running and the oil cooler circulates all the time.
There was a different way to purge the hydraulic system posted on here and that is how I did mine but it requires about 30 to 40 gallons on hydraulic fluid.
I will see if I can find it and post it as it’s quite involved.
Basic process was disconnecting filter return and dumping that into a big bucket, I used a 40 gallon trash pail.
Then you start the backhoe intermittently moving certain functions as you do it and immediately shut it down. That way, you are not mixing good and bad oil.
The way I did it was the way Wille59 describes it.
Good luck.
Thank you for this link. I have seen it already. I have read every post about this. But I’m not sure this will work on a 580B? The filter hoses run through the valve. Seems the way for the 580B to do it would be to drain from the return lines in front of radiator, where they Tee and go into the reservoir towers. Atleast that’s were I think they return to. I doubt it’s the suction since they are at the top of the reservoir.
 

Sslane

Member
Joined
Mar 7, 2025
Messages
15
Location
California
Thank you for this link. I have seen it already. I have read every post about this. But I’m not sure this will work on a 580B? The filter hoses run through the valve. Seems the way for the 580B to do it would be to drain from the return lines in front of radiator, where they Tee and go into the reservoir towers. Atleast that’s were I think they return to. I doubt it’s the suction since they are at the top of the reservoir.
Also, so I’m kind of confused how Tinkers processed worked for him if the pump instantly contaminates the tank of new fluid, assuming the pump recirculates the oil. Maybe when he starts the motor and starts to cycle the oil through the open cyld. lines, he does it quickly enough that the pump doesn’t have time or there isn’t enough pressure to recirculate the oil?
 

Tinkerer

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Also, so I’m kind of confused how Tinkers processed worked for him if the pump instantly contaminates the tank of new fluid, assuming the pump recirculates the oil. Maybe when he starts the motor and starts to cycle the oil through the open cylinder lines, he does it quickly enough that the pump doesn’t have time or there isn’t enough pressure to recirculate the oil?
I ran the engine only long enough to to flush one individual circuit at a time.
I flushed one side of a cylinder until clean oil started to flow - shut off the motor and reconnected the hose.
Then retracted or extended the cylinder to flush the other side of the cylinder and then put the hose back on.
The cylinders that work in unison both have to be done at the same time because they interact with each other.
That would be the loader hoist and bucket, and the swing cylinders on the backhoe.

There was no noticeable contamination in the reservoir at all.
When I was done the oil in the sight glass looked like new oil -- as it should.

Just because my method worked so well does not mean it will for someone else.

To eliminate confusion rea
Below is from the 580B service manual.
b.jpg
 
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