Milky hydraulic oil

[1bigtime379]

So I have this old excavator and it got what I presume water in the hydraulic oil. Anyways like 26 pales and 3 flushes later I finally got clear oil after running the machine. I ran it for a few hours, checked the oil again, still clear
I suspected it was my vent cap that got water in there so that was replaced and I tarped the entire machine. I checked the oil today (didn’t even rain last night) and it’s fairly cloudy again. How is this possible? Remaining water in the system getting back into the tank?
I have added a picture of the oil from last night and today before I fired up the machine. This is getting really expensive and frustrating. Any insight would be great.
My machine is a 1994 case 9030

 

[BobCatBob]

Went through this myself…..took 3 full flushes (6 barrels of 46 hydraulic) for my crane…it’s expensive, but necessary. I get the oil hot and find a little steam coming out of the breather…..burning off residual moisture. It’s when these machines sit and thermo cycle attracting moisture…..key is to run ‘em hot every now and then imho.

 

[Island_catguy]

Yeah you can flush and flush, but there is still a lot of volume in the cylinders. I siphoned out a tank, filled with fresh, put the return in a drum and kept topping up the tank while actuating the cylinders. After the first drum boss wasn’t happy. Told him well this is cheaper than me changing all the seals. Ended up taking 3 drums. And mine was straight up milk colored.

 

[1bigtime379]

Went through this myself…..took 3 full flushes (6 barrels of 46 hydraulic) for my crane…it’s expensive, but necessary. I get the oil hot and find a little steam coming out of the breather…..burning off residual moisture. It’s when these machines sit and thermo cycle attracting moisture…..key is to run ‘em hot every now and then imho.

My machine does sit a lot and doesn’t work too hard. Maybe I don’t get the oil hot enough…
However when I took that sample on the left the oil was quite hot, almost hard to touch.. and it wasn’t milky. I don’t understand how any moisture would have contaminated that oil overnight with a new vent cap and the entire machine tarped…
The hydraulic cooler doesn’t use coolant as far as I can tell, so I have no idea where water could be coming in

 

[HarleyHappy]

First, the tarp helps induce condensation. Second, a few ounces of water will make the whole 18 gallons or whatever, look cloudy. My backhoe still has a bit of water in the hydraulic oil after flushing and following a process described in here.
The only thing I did differently, was add a gate valve instead of a drain plug for the hydraulic tank.
When it sits for a while, I make a habit of draining the water out of the bottom of the tank. Over time, the am of water has reduced to just a cap full.
If the hydraulic fluid has water that has emulsified, it will never come out, without heat or drying.

https://www.heavyequipmentforums.com/threads/getting-all-hydraulic-fluid-out.19687/

 

[1bigtime379]

First, the tarp helps induce condensation. Second, a few ounces of water will make the whole 18 gallons or whatever, look cloudy. My backhoe still has a bit of water in the hydraulic oil after flushing and following a process described in here.
The only thing I did differently, was add a gate valve instead of a drain plug for the hydraulic tank.
When it sits for a while, I make a habit of draining the water out of the bottom of the tank. Over time, the am of water has reduced to just a cap full.
If the hydraulic fluid has water that has emulsified, it will never come out, without heat or drying.

https://www.heavyequipmentforums.com/threads/getting-all-hydraulic-fluid-out.19687/

Thank you for your input. I do have a valve at the bottom of the tank so since I only use my machine on the weekends I guess I could get in the habit of draining a bit out before use
Would you suggest not to use a tarp at all then? I do have a brand new cap on it now however I am so scared to introduce water back in there I was tarping it off as I don’t have a roof to store my machine under

 

[HarleyHappy]

Not many people have a roof. Machines sit outside their whole life.
Unless there could be water intrusion through a breather or a bad seal on the hydraulic fill cap, there is no other way for water to get in, other than condensation OR bad cylinder seals that let water in.
When my stabilizer seals were bad and I stored the machine with the stabilizers up, as soon as I moved them, I sucked some water through the dust seal and into the cylinder, more than likely.
Now, all my seals are done and I have less and less water.

 

[1bigtime379]

Not many people have a roof. Machines sit outside their whole life.
Unless there could be water intrusion through a breather or a bad seal on the hydraulic fill cap, there is no other way for water to get in, other than condensation OR bad cylinder seals that let water in.
When my stabilizer seals were bad and I stored the machine with the stabilizers up, as soon as I moved them, I sucked some water through the dust seal and into the cylinder, more than likely.
Now, all my seals are done and I have less and less water.

Would you suggest I do another flush the way Island_catguy suggested or just run the machine good and hot for a while?

 

[HarleyHappy]

I ended up putting the return before the filter, in a big trash barrel and kept adding hydraulic fluid. I would start the engine up, with the oil cooler immediately dumping into the trash barrel and move a couple of the cylinders from closed to open and shut the machine off. Refill tank and repeat. For a system that holds 12 or 15 gallons, I used 45 to 50 gallons.
My hydraulic fluid was emulsified.
I then let it separate and tried draining off most of the water.
Then I gave 40 gallons or so of new hydraulic fluid to my brother, who works at a GM dealer and has 3 waste oil burners.
Then he determined that new hydraulic fluid doesn’t burn as it has some additive.
Plugged all 3 up.
Wasn’t too pleased, with helping me get rid of basically new hydraulic oil.
I used TS cheap hydraulic fluid for the flush.
Whole thing was messy, dumped quite a bit of fluid on the line, when I forgot to open a ball valve and blew up an oil cooler line.
Friggin nightmare, I hope to never repeat.
Good thing was my hands were nice and smooth for a bit.
Depends on how much water is in it.

 

[HarleyHappy]

Question, those bottles, were they taken from the bottom of the tank?
If so, remember water is heavier than oil, so that’s why I put a gate valve in. I just drain out water, which right now would be 2 cap fulls and shut it when clear oil comes out.

 

[1bigtime379]

Question, those bottles, were they taken from the bottom of the tank?
If so, remember water is heavier than oil, so that’s why I put a gate valve in. I just drain out water, which right now would be 2 cap fulls and shut it when clear oil comes out.

Thank you for that information, HarleyHappy, and no those are samples taken from the top of the tank. The clear one was the night before when the oil was hot, the second one the day after before firing up

 

[Ashish]

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