Anyone have any suggestions on getting water contaminated hydraulic oil out of the system?

[ts360]

My 690ELC got water in the hydraulic oil at some point and I've been struggling with it ever since. I think I've fixed where it was coming from(boom lift cylinders) but changing the oil in the tank never makes it any better. I know there is a lot of oil in the rest of the system but I would have thought that it would eventually clear up with multiple tank changes but it never does. I suppose I have two questions, is there anything that can be added to a system this large that anyone has had any luck with getting rid of water? And if that is not an option, does anyone have any advice to flushing a system like this? Thank you for any info

 

[bigboytoy]

hmm ... fill tank with fresh oil ... divert return line ... stroke cylinders ... -- or -- draw out water after it sets and separates, it might take days? .. it will be at bottom of tank ... I would think a small amount would evaporate when the oil gets hot and go out the vent on the tank ...

 

[ts360]

hmm ... fill tank with fresh oil ... divert return line ... stroke cylinders ... -- or -- draw out water after it sets and separates, it might take days? .. it will be at bottom of tank ... I would think a small amount would evaporate when the oil gets hot and go out the vent on the tank ...

I would think that it would separate as well but it doesn't in hydraulic oil. It seems like once it gets churned up, it's milky forever. This machine just had a separate break down(engine front seal) and sat for months until I had a chance to fix it, and the oil never separated. I think I'm going to have to try your first suggestion, thanks for the idea, I was pondering unhooking it at each individual cylinder but if I could unhook a main return somewhere, that would be great.

 

[Lagwagon]

This is what I did. Drained tank, cracked all cylinders and manually stroked the oil out of both ends, cracked all lines coming out of centre joint and drive motors, cracked lowest ports on main control valve. Cracked all boom, stick hoses. Pulled oil cooler and drained. Drained pumps and main suction hose. Replaced all filters. I had a good half inch thick layer of watery sludge at the bottom of my tank so I scrubbed it clean. My manual states 200l to change oil and I recovered 280l so yeah there’s heaps more in the system outside of the tank. This process takes time as is very messy but is the only way imo.

 

[Delmer]

There's lagwagon's method, or there's methods described where you fill the tank with clean fluid and flush each hose and cylinder in turn with clean fluid with the machine running.

There are also ways to dry oil either on the machine or off the machine, the simplest involve either heating the oil to boiling (relatively dangerous) or heating the oil slightly and bubbling air through the oil. Air bubbling is practical on the machine if the hydraulic reservoir is accessible and you can insulate the upper part so the water doesn't all condense inside the tank. A junk refrigerator compressor works nicely for the small air volume, get some steel 1/4 or so brake line to stick in the tank, and any method that will heat the hydraulic oil up to 120F or so. If you have, or can add a 1" NPT port, you can screw in a water heater element, if it's rated 240V then it will run at 1/4 the wattage at 120V. I like to use a vent hose going several feet with the air supply brake line inside it, but the vent hose has to run downhill from the outlet to drain condensation out. Set that up so you can still use the machine, and run it for a few hours after every time you use the machine until there's no more condensation.

 

[bigboytoy]

If the oil is not separating staying milky ... sounds like its too thick ... I can see where heat will help ... I have an old 1983 JD510b with 8k hrs that will leak everywhere if oil is too thin when its too thick it sounds like a saw blade in the pump ... lol ... 20w (iso 68) or 15w (iso 45) are typical ideal weights for old stuff ... iso 32 10w should separate well but may be too thin .. I mix in iso 100 to thicken it up ... I cheat lol ... but a old machine doesn't complain much as I can just take it out back and let it rust...lol

 

[Tones]

Because oil and water are 2 different weights I often thought of using a cream separator like we had on the farm and putting the oil through it to remove the water. I have no idea if it would work but finding a separator these days would be the hardest part and I'd sure be interested to hear if some one tried it out and whether it was successful of not.

 

[funwithfuel]

How about pulling 25" of vacuum on the tank? Just like air conditioning, it will boil the moisture out of the fluid. It'll take a long time but it's cheaper than oil changes. If you want to point a torpedo heater at the tank to raise the temp up to 150° or so, that might help.
Is this what Delmer is describing as "bubbling?" If so, I think he's onto something.

 

[1693TA]

You need to get the oil hot and drain the main reservoir of the machine. You can do this easily by curling something like the boom against either it's physical stop, or something immovable. Hold the pressure on allowing the hydraulic oil pressure to spill over the main system pressure relief valve. Allow the oil to get very warm but not boiling in the system. Do this about 10 minutes checking temperature constantly to not overdo it. You don't want the oil to boil as the anti wear additive(s) boil away first. After the oil is let's say 200 degrees, shut the machine down for two hours with access covers opened up to facilitate cooling airflow. This action will cause separation of the water from the oil citing specific gravity of both substances. Once a couple hours of cooldown has elapsed, replicate the scenario again. Water will always separate out to the bottom of the reservoir. Use a drain cock, (usually provided) or a tube and vacuum source to withdraw the water pooled in the bottom.

 

[ts360]

Thanks for all of the valuable ideas and information everyone. I finally got all of the milky oil in the tank drained out today and got all of the oil that I could out of the oil cooler, lift cylinders, stick cylinder, and bucket cylinder. Tomorrow I'm going to clean the tank, drain anything else that I can then add new oil. I'm thinking this should make the oil a lot better but I'll probably still have to use some of these suggestions and drain the milky stuff off the bottom of the tank before I start the machine after it sits overnight until it completely clears up. Thanks again for the information, hopefully this is the last time for a while that I have to do such an expensive oil change

 

[Delmer]

A centrifuge is standard equipment in lots of industrial oil uses, and it will clean the water and lots of other dirt out of oil. You could probably buy a couple excavators for what an oil centrifuge will cost you though. Vacuum will work great also, but I've never found a hydraulic tank that will hold suction, some would probably crinkle if you could get that much suction, they leak air first. If you're going to pump the oil out, then combining all three would be ideal, air bubbling, heat, vacuum and even a simple dirt centrifuge, but for just water, air bubbling is the simplest relatively effective way I've found.

 

[1693TA]

If your drain cock is readily accessible I would drain that hydraulic reservoir each morning of water accumulation till moisture is no longer present. Cycling the functions such as a good days work will move the water along eventually accumulating in the main reservoir.

 

[ts360]

If your drain cock is readily accessible I would drain that hydraulic reservoir each morning of water accumulation till moisture is no longer present. Cycling the functions such as a good days work will move the water along eventually accumulating in the main reservoir.

I was hoping to be able to do that, but after draining all of the oil from the tank, cleaning the tank, draining every line that I could reasonably access, and from all the cylinders, I added 50 gallons of clean oil and it turned back into the same yellow muck as before almost instantly with the machine running. After setting overnight, the oil on the bottom of the tank looks the same as the oil on the top of the tank. I am definitely going to have to give some of the suggestions I've gotten a try.

 

[Steve Austin]

I would not operate the excavator no longer than i had to with water in hydraulic oil.
I assume it has. The Linde pump from my experience those pumps do not like any kind of constatation.
Before the filter caddy days Deere would have us disconnect the return as mentioned in an earlier post.
I made up an extension hose to connect to return hose to run into a waste oil drum or drums!
They had us drain reservoir and fill with new oil and cycle each function keeping reservoir full of new oil all the time.
Change filters afterwards. Deere had a cleanup filter for the 690E but it did nothing for water.
This took a lot of time, patience. oil and money but not as much as a component failure will cost.
Of course, make sure you have the source of water entry resolved first including any five-gallon cans of hydraulic oil that have been stored outdoors. Check all cylinder wiper seals, we had a Hitachi that had water in hydraulic and only thing we found was bucket cylinder wiper seal was completely destroyed.

 

[Steve Austin]

I meant pumps do not like any kind of contamination not what ever spell check inserted.

 

[ts360]

Is there only one return? I would assume it is the big one coming from the top of the oil cooler to the tank but there are also smaller ones higher up on the tank. Thanks

Before the filter caddy days Deere would have us disconnect the return as mentioned in an earlier post.
I made up an extension hose to connect to return hose to run into a waste oil drum or drums!
They had us drain reservoir and fill with new oil and cycle each function keeping reservoir full of new oil all the time.

 

[Steve Austin]

Hose 15 from control valve to reservoir you want to divert from control valve to waste oil drum. Just going by memory not 100% sure been a while.

 

[Spiva Const]

When I get time I’m going to take a small tank and add contaminated hydraulic fluid and put it under a vacuum to see if that may work, sounds like a reasonable idea.
I have an old champ forklift that got water in the system thru a poor filler cap design, after draining the tank and changing the filter it still is milky. I did add a gallon of Lucas hydraulic booster and leak additive and it definitely made a difference in smoothing out the operation of the rams and pump.
I also wonder if a block heater installed in the oil level or drain pipe thread port would help vaporize the moisture. Just would want to make sure it doesn’t get to hot to be dangerous.

 

[Delmer]

A vacuum will rapidly drop the temp of the oil as the boiling water will remove heat and lower the boiling point. Adding heat is so much simpler and more effective, for getting most of the water out of oil at least.

A water heater element run on 120V or less will be much lower watt density, so less likely to burn the oil on the surface. The size of the reservoir will determine how hot the oil gets overall. The amount of air and water vapor leaving will help keep it cool, but watch that the temp doesn't rise as the water content drops and there is less water evaporating.

 

[ts360]

A vacuum will rapidly drop the temp of the oil as the boiling water will remove heat and lower the boiling point. Adding heat is so much simpler and more effective, for getting most of the water out of oil at least.

A water heater element run on 120V or less will be much lower watt density, so less likely to burn the oil on the surface. The size of the reservoir will determine how hot the oil gets overall. The amount of air and water vapor leaving will help keep it cool, but watch that the temp doesn't rise as the water content drops and there is less water evaporating.

Unfortunately I don't have power where the machine is so I'll have to drain oil and bring it with me to heat it up. I'm definitely going to give it a try so I can re use as much oil as possible.