milky hydraulic oil

[sterjess]

I have an old Ford 2000 tractor that had milky hyd fluid, took changing the reservoir 3 times til it wasnt' milky anymore.

[Nige]

I've never had to deal with a massive hydraulic system but had a 10 gallon system get drenched with water, drained it and seperated it. After filtering it still looked milky so I had it in a steel barrel and carefully heated it to 220f and let it vapor off for a couple hours. Seemed to become crystal clear, let it cool and put it back in. Went on the turkey fryer idea, nice slow smooth heating.

My 2 cents worth .........

1. First off, all mineral-based hydraulic oils are hygroscopic. That means they have a tendency to attract water, just like brake fluid only not quite as bad.

2. Water can be present mixed in hydraulic oil in 3 distinct forms.
a) Dissolved - you can't see this.
b) Separated - what sits in the bottom of the tank (if any).
c) Emulsified - the milky colour you can see.

3. The additive package in the oil is designed to work on water particles in the oil in 2 of the 3 cases above.
a) Part of the package assists in the absorption of water into the oil - (dissolved).
b) Another part of the package is designed to help small water particles coalesce and become so large that they fall out of the oil to the bottom of the tank - (separated).

4. The fact that the oil is milky in a hydraulic system would suggest that the additive package designed to assist in treating water (see above) has depleted to such an extent that it can no longer cope and so the water is neither dissolved nor falls out of the oil and so it mixes to form the milky emulsion you can clearly see.

5. Typically in the case of an emulsified oil you might have in the range of 1000-5000ppm (parts/million) of water actually dissolved in the oil, & a similar amount in emulsion.

6. Careful heating will no doubt drive off the visible water and return the oil to a clear bright colour again, but you are not doing anything about the dissolved water in the oil. The additive has chemically combined with it and nothing you can do will "un-combine" the water & oil mixture.

7. As per my example in 5 above by heating you have only driven off half the water anyway.

8. The critical part. If the additive package in the oil designed to treat water has depleted to a point where it no longer works then what about all the other additives present in the oil designed to prevent corrosion, foaming, anti-wear, etc, are they more than likely not depleted also ..?

Hope this might shed a bit more light on the subject.

[fast_st]

Thanks for the excellent info Nige. The worst I have seen is on the 'free' dozer, the trans was 'frozen' and wouldn't shift, backed it up to a salamander for 4 hours and then drained a couple gallons of clear water from the gearbox before the gloppy white foamy vanilla frappe came out. The Manual states that in cases of bad contamination, refill the gearbox with diesel and run it around, drain and refill with gear oil, that worked perfectly

[Nige]

You're welcome ...........

In cases like the one that started this thread often you can't see the wood for the trees, and until you step back and think about it a lot of the points mentioned above don't become apparent.

Changing tack slightly, the soap that you would use in your dishwasher (you need the non-foaming type) at home is extremely good for getting cooling systems clean after they have been contaminated with oil.

Believe me if you get an engine oil system contaminated with glycol you don't even want to know what that involves to get the last traces of glycol out - it's a compound called butyl cellusolve that needs a Hazard Materials Permit to even transport ........

[cottontop]

I have a 1963 ford 2000 tractor. My hydraulic fluid was really milky and the lift would not work, I found by just changing the fluid did nothing so I tried the following. I drained all the fluid from the middle, Hydraulic resevoir and loosened the bleeder valve on the pump, near the engine, I let this drain overnight, next I got 2 gallon of diesel fuel and put it in the resevoir and let the tractor run about 10 minutes, I tried the lift and it slowly raised, I let this set over night and then drained the fuel for some 4 hours to be sure it was out. This is the important part. Go to your FORD dealorship and get non foaming oil, G-134 is what I used, yes it cost more but will not foam. I filled the system, 2 gallons for my tractor, Now the lift works. I think it is a little slower but it works,.. I will not guarantee this on every tractor but it worked with mine.

[Garrie Denny]

Pick Nige/s brain time again. Hi N, Garrie here again, that 10w40 oil i put in my dozer (Fiatci70) when i drain it will it be ok to use in my hydraulic tank, its only been in the motor 10 odd hours and as clean as when it went in, the reason is that the lever o-ring on my blade raiser and lowerer leaks like a seive sometimes and im forever topping up tjhe tan, thanks Garrie

[Nige]

Garrie, in view of the age of your machine and so long as the oil is clean I wouldn't have a problem using that oil in the hydraulic system. Just make sure you don't get dirt in it during the transfer process.

What not fix the leak ya slack barsteward .....??

Note for our US members ........... Australia, the country where your best mate is a "right bas*ard" and your worst enemy is a "bit of a bas*ard" ............

[Garrie Denny]

Thaks for your reply nige,yes I admit I am getting slack in my old age ill admit, and it is on the to do list, just that I work down in brisvegas and only get home to Gin-Gin every 3 or four weeks and i only want to play on my toy then, By the way your advice on my hyrdraulic/diesel mix up on the bob-cat was excellent i have now got rid of that mix i drained over about 4 tank fill in the dozer without any difference in motor operation. Thanks, Garrie.

[yzman14]

normaly thats from water in oil.

[HeavyMan]

My 2 cents worth .........

1. First off, all mineral-based hydraulic oils are hygroscopic. That means they have a tendency to attract water, just like brake fluid only not quite as bad.

2. Water can be present mixed in hydraulic oil in 3 distinct forms.
a) Dissolved - you can't see this.
b) Separated - what sits in the bottom of the tank (if any).
c) Emulsified - the milky colour you can see.

3. The additive package in the oil is designed to work on water particles in the oil in 2 of the 3 cases above.
a) Part of the package assists in the absorption of water into the oil - (dissolved).
b) Another part of the package is designed to help small water particles coalesce and become so large that they fall out of the oil to the bottom of the tank - (separated).

4. The fact that the oil is milky in a hydraulic system would suggest that the additive package designed to assist in treating water (see above) has depleted to such an extent that it can no longer cope and so the water is neither dissolved nor falls out of the oil and so it mixes to form the milky emulsion you can clearly see.

5. Typically in the case of an emulsified oil you might have in the range of 1000-5000ppm (parts/million) of water actually dissolved in the oil, & a similar amount in emulsion.

6. Careful heating will no doubt drive off the visible water and return the oil to a clear bright colour again, but you are not doing anything about the dissolved water in the oil. The additive has chemically combined with it and nothing you can do will "un-combine" the water & oil mixture.

7. As per my example in 5 above by heating you have only driven off half the water anyway.

8. The critical part. If the additive package in the oil designed to treat water has depleted to a point where it no longer works then what about all the other additives present in the oil designed to prevent corrosion, foaming, anti-wear, etc, are they more than likely not depleted also ..?

Hope this might shed a bit more light on the subject.

Dealing with water in hydraulic fluid



If you have worked with hydraulic equipment for any length of time, it's likely that you've come across a hydraulic system with cloudy oil. Oil becomes cloudy when it is contaminated with water above its saturation level. The saturation level is the amount of water that can dissolve in the oil's molecular chemistry and is typically 200 - 300 ppm at 68°F (20°C) for mineral hydraulic oil. Note that if hydraulic oil is cloudy it indicates that a minimum of 200 - 300 ppm of water is present. I recently audited a hydraulic system with cloudy oil that was found to contain greater than 1% (10,000 ppm) water.

Why is water in hydraulic fluid bad?

Water in hydraulic fluid:

Depletes some additives and reacts with others to form corrosive by-products which attack some metals.
Reduces lubricant film-strength, which leaves critical surfaces vulnerable to wear and corrosion.
Reduces filterability and clogs filters.
Increases air entrainment ability.
Increases the likelihood of cavitation occurring.
How much water is too much?

A number of factors need to be considered when selecting water contamination targets, including the type of hydraulic system and reliability objectives for the equipment. It's always wise to control water contamination at the lowest levels that can reasonably be achieved, ideally below the oil's saturation point at operating temperature.

Water removal methods

Methods for removing free (unstable suspension) and emulsified (stable suspension) water include:

polymeric filters;
vacuum distillation; and
headspace dehumidification.
Vacuum distillation and headspace dehumidification also remove dissolved water.
Polymeric filters - These look like conventional particulate filters, however the media is impregnated with a super-absorbent polymer. Water causes the polymer to swell, which traps the water within the media. Polymeric filters are best suited for removing small volumes of water and/or maintaining water contamination within pre-determined limits.

Vacuum distillation - This technique employs a combination of heat and vacuum. At 25 inches Hg, water boils at 133°F (56°C). This enables water to be removed at a temperature that does not damage the oil or its additives.

Headspace dehumidification - This method involves circulating and dehumidifying air from the reservoir headspace. Water in the oil migrates to the dry air in the headspace and is eventually removed by the dehumidifier.

In the case of small systems with high levels of water contamination, changing the oil may be more cost-effective than using any of the above methods of water removal.

Prevention is better than cure

Like all other forms of contamination, preventing water ingress is cheaper than removing it from the oil. A major point of water ingression is through the reservoir headspace. Many hydraulic system reservoirs are fitted with breather caps that allow moisture (and particles) to enter the reservoir as the fluid volume changes through either thermal expansion and contraction, or the actuation of cylinders.

Replacing the standard breather cap with a hygroscopic breather will eliminate the ingression of moisture and particles through the reservoir's vent. These breathers combine a woven-polyester media that filters particles as small as 3 microns, with silica gel desiccant to remove water vapor from incoming air. The result is relative humidity levels within the reservoir headspace that make condensation unlikely, therefore reducing water contamination of the oil.
http://www.insidersecretstohydraulic...lic-fluid.html

[MatthewG]

Good info here