Milky hydraulic fliud.

[rasorbackq]

Last week did my maintenance by replacing the engine oil and hydraulic fluids in my HST Branson tractor . Noticed today the site glass showed milky foamy color fluid. Some how it has gotten contaminated. . Couple questions .
Does milky color only mean water has gotten in? or can a mixing of 2 oils type fluids cause this?

So since Ive been using the tractor front bucket I have to assume the milky fluids also in the hydraulic lines . I know the fluid needs to be changed again but how does one do this to remove all the milky oil from the systems. It holds 10 gallons at a cost of $200 to replace. Trying not to drain and refill with the rear end of tractor again with filters also only to have it milky in a day after the buckets used again.

 

[Hay Dude]

Last week did my maintenance by replacing the engine oil and hydraulic fluids in my HST Branson tractor . Noticed today the site glass showed milky foamy color fluid. Some how it has gotten contaminated. . Couple questions .
Does milky color only mean water has gotten in? or can a mixing of 2 oils type fluids cause this?

So since Ive been using the tractor front bucket I have to assume the milky fluids also in the hydraulic lines . I know the fluid needs to be changed again but how does one do this to remove all the milky oil from the systems. It holds 10 gallons at a cost of $200 to replace. Trying not to drain and refill with the rear end of tractor again with filters also only to have it milky in a day after the buckets used again.

A friend of mine just bought a flooded tractor (we had an epic flood here in September).
It had milky hydraulic fluids. What he did was collect used hydraulic oil from a couple local farmers (me one of them), drained the milky hydraulic fluid and filled with used hydraulic fluid 3 times until none of the used fluid had a milky appearance. On the 3rd draining, he refilled with new hydraulic fluid and filters.
You could go to dealers in your area and give them empty oil jugs. Ask them to save discarded hydraulic fluid in them and do same thing.

 

[sea2summit]

I’ve never heard of mixing oils causing milky fluid.

I have a change worth of fluid I haven’t taken to disposal yet…guess Hay Dude just gave me a good reason to hang onto it, never thought of that.

 

[woody]

need to figure how it got milky is it water contamination or is it sucking air some where? My B26 was sucking so much air it was foaming out the vent and looked milky. Is the level higher than when you last checked it. Was the oil you drained out milky looking?

 

[Fxfymn413]

Last week did my maintenance by replacing the engine oil and hydraulic fluids in my HST Branson tractor . Noticed today the site glass showed milky foamy color fluid.

I assume there was no water in the oil you drained out so my bet is you have air in the system since you just changed the fluid. Let it sit and then check it. And if it is water letting it sit will allow the water to separate from the oil so when you open the drain you will get water before you get oil which will allow you to diagnose how much water is getting into the system.

The likelihood of water appearing immediately after an oil change seems pretty slim when there was no sign of prior contamination.

 

[BeezFun]

take a teaspoon of the old fluid and heat it with a torch. If it pops and sizzles like bacon frying that's water. If not, it was probably air.

 

[5030]

need to figure how it got milky is it water contamination or is it sucking air some where? My B26 was sucking so much air it was foaming out the vent and looked milky. Is the level higher than when you last checked it. Was the oil you drained out milky looking?

You wash it? How it gets in milky = water, always. Foaming is usually2 not compatible fluids. Ever bother draining the bellhousing? If not you should.

 

[rasorbackq]

need to figure how it got milky is it water contamination or is it sucking air some where? My B26 was sucking so much air it was foaming out the vent and looked milky. Is the level higher than when you last checked it. Was the oil you drained out milky looking?

The oil I changed was not milky at all.
Golden dark but was at the 300 hrs schedule. I dont remember replacing the plug on the oil filler. Have to go look.

 

[rasorbackq]

Filler plug was installed . I also checked the vent plug for filling . It too was there and tight. When I did the machinate I over tightened one of the filters and gasket did not sit right. Causing the real big mess on the floor.
I put a drip pan under it that was not clean to catch the fluid that was running out . By morning it was stopped I could see the issue with the gasket . Replaced the filter again.
Filled with what I had left then used the drip pan which was about 2 gallons in it.
I poured it in until the dirt from the pan started to show then I stopped.
There was no water in the drip tray before I used it.
So all I did was drained from 2 spots under neath . Removed 2 filters and opened the fill vent and removed the fill cap . Either filter is leaking .
Did not wash the tractor.
In barn every night.

 

[rasorbackq]

The likelihood of water appearing immediately after an oil change seems pretty slim when there was no sign of prior contamination.

I agree

 

[Boss 302]

Sounds like air to me, like said drain it in a clean bucket and see if it clears up

 

[rScotty]

The milky look is caused by either air or water. No, mixing different types of trans/hydraulic fluids doesn't cause that.

To determine which it is - air or water - check it in the morning before starting. If it is air (micro bubbles) it will have cleared up noticibly.

If it is water it will eventually turn slimy, change fluid a few times and don't leave it out in the rain without a tarp.

If air, you have a suction leak between the sump and the high pressure pump. Usually it's a fitting, but can be around a filter.

Good luck.

 

[rasorbackq]

Dont understand the air sucking comments.. The filler cap has a hole in it to allow air in . Its is U shaped so pointing down.
If it is a fitting leaking air . shouldnt it leak when parked??
I will check out the filters again . Need the tractor today to clear snow. First snow fall for the year . Only 5-6 inches.

 

[rScotty]

Dont understand the air sucking comments.. The filler cap has a hole in it to allow air in . Its is U shaped so pointing down.
If it is a fitting leaking air . shouldnt it leak when parked??
I will check out the filters again . Need the tractor today to clear snow. First snow fall for the year . Only 5-6 inches.

Fair question. So here we go...Good call on the vent. It really is the key.

The vent in filler cap does two things: Most important is that it allows some air into the sump cavity to replace the reduced fluid volume of in the sump which happens when some of the fluid in the sump is initially moved up into the hydraulic pump. Allowing the air to enter via the vent maintains the atmospheric pressure in the sump. Since the high pressure hydraulic pump is above the level of the fluid in the sump, that atmospheric air pressure is necessary because ultimately that atmospheric air pressure is what forces fluid up to the high pressure pump.
The high pressure pump helps to suck fluid up to itself because when the pump starts to spin it reduces the pressure in its intake line. We call that "suction". but technically it is just different pressures...when the pump spins, air pressure in the sump is higher than the pressure at the intake of the pump, and that higher pressure forces fluid up to the pump.

Now if there is anywhere along the line between the sump and the pump where air can sneak in, then it will. That is called a suction leak. Sometimes it is a tiny split in the end of a hose between the sump and the pump. But can be anywhere. The result is that the pump tries to compress the air into the oil and that makes these microbubbles that make the fluid look cloudy. And just as you say, with a suction leak you won't see any oil leaking out externally until you turn it off. That's because air is being sucked in while it is running. But sometimes when the engine is shut off and just sitting there the suction leak will declare itself by dropping some oil out as the pump's oil slowly returns to the sump because of gravity.

I said that the air vent in the filler cap does two things. Replacing air in the sump is one more thing. The other is that it allows air to flow in and out of the sump as the sump and fluid heats and cools.
Both functions that the air vent does are aimed at maintaining a constant atmospheric pressure on the fluid in the sump.

Does that help?
rScotty

 

[woody]

Mine was a bad seal on the pump and it did not leak a drop. That being said I don't believe it's your pump must be something you changed or cleaned or maybe over tightened, hopefully yours will show itself in the form of a small leak.

 

[rasorbackq]

Fair question. So here we go...Good call on the vent. It really is the key.

The vent in filler cap does two things: Most important is that it allows some air into the sump cavity to replace the reduced fluid volume of in the sump which happens when some of the fluid in the sump is initially moved up into the hydraulic pump. Allowing the air to enter via the vent maintains the atmospheric pressure in the sump. Since the high pressure hydraulic pump is above the level of the fluid in the sump, that atmospheric air pressure is necessary because ultimately that atmospheric air pressure is what forces fluid up to the high pressure pump.
The high pressure pump helps to suck fluid up to itself because when the pump starts to spin it reduces the pressure in its intake line. We call that "suction". but technically it is just different pressures...when the pump spins, air pressure in the sump is higher than the pressure at the intake of the pump, and that higher pressure forces fluid up to the pump.

Now if there is anywhere along the line between the sump and the pump where air can sneak in, then it will. That is called a suction leak. Sometimes it is a tiny split in the end of a hose between the sump and the pump. But can be anywhere. The result is that the pump tries to compress the air into the oil and that makes these microbubbles that make the fluid look cloudy. And just as you say, with a suction leak you won't see any oil leaking out externally until you turn it off. That's because air is being sucked in while it is running. But sometimes when the engine is shut off and just sitting there the suction leak will declare itself by dropping some oil out as the pump's oil slowly returns to the sump because of gravity.

I said that the air vent in the filler cap does two things. Replacing air in the sump is one more thing. The other is that it allows air to flow in and out of the sump as the sump and fluid heats and cools.
Both functions that the air vent does are aimed at maintaining a constant atmospheric pressure on the fluid in the sump.

Does that help?
rScotty

Yes Understood.
So it was to dark to see the site glass in the barn. But I did pull the plug from bottom of transmission I guess it is. Oil was clean and clear . No milky.
So yes I am getting air from somewhere. As woody has said I must have over tightened one of 2 things. Can only be the filters. Was all snow under machine this morning didn't see any fluids .
on the snow

 

[Fxfymn413]

When doing any trouble shooting do not overlook what occurred just before the trouble started and never start talking yourself into thinking it is the worse possible thing that could occur.

In this case you changed the oil and filters. Since nature abhors a vacuum air immediately went into the system to replace the oil you drained out and my bet is that some of it got into a high spot in the system, got emulsified into the oil, and has to work its way out.

Unless you have come up with a way to make water with the tractor while it sits there is no chance you got water into the system since you said you did not wash it or expose it to any other water source. Be patient and it will self cure.

And not to nag but using the spilled oil was probably not too wise. I get it since I'm as cheap er..thrifty as they come but 5 gallons of oil around $100.00; repairing a dirt contaminated hydraulic system; way more than that. And a trip to town to buy oil..a few hours; repair time..a few weeks.

 

[Smokeydog]

Saw on market place a converted water heater used to remove water from hydraulic oil for large excavator size equipment. A novel approach I didn’t know existed.

 

[rasorbackq]

Update:
let tractor sit due to weather for a couple days . Oil in site glass was new oil colour. and after 15 minutes of use it was milky cloudy again.
Still had no time to check filters

 

[rScotty]

Update:
let tractor sit due to weather for a couple days . Oil in site glass was new oil colour. and after 15 minutes of use it was milky cloudy again.
Still had no time to check filters

I'd say that is a typical suction side air leak. Others may want to chime in too.

But it sounds to me that what you are seeing are micro-bubbles in the hydraulic oil. Downside is that as the hydraulic pump makes those bubbles it also bursts them and popping the bubbles creates micro-pitting on the hydraulic pump face - which will degrade the mirror finish on the pump gears and eventually ruin it.

So unless someone has another theory I'm going to say what you have is air getting into the hydraulic pump. It can be coming in by two pathways. The easiest to fix path is somewhere in the suction line somewhere between the sump and the pump - that includes the filter seals and especially the hose ends. Often a suction leak in that path will cause oil to slowly drip out when the engine is not running. That's how to find it. This is when you WANT to have a leak to fix. The problem is this is not 100% sure if you don't find a leak. That is because although all suction path air leaks do put air into the hydraulic fluid when running, not all of them leak oil when not running. But most do.

The other way air can come in is entering past the oil seal inside the hydrauic pump where the pump is being driven by the engine. You suspect that when you can't find a leak as above.

Neither one is all that difficult to fix, but has to be done.

good luck,
rScotty