Water in hydraulic reservoir?

[Hoho223]

I have a first generation Bobcat CT120 (2012). I changed my hydraulic fluid yesterday and you can see the results by the picture. The dipstick NEVER showed that color. I have an intact screw cap on fill hole…ALWAYS. The fluid was in the clear container overnight and there was no oil/water separation line. I have a hydrostatic drive. If anyone can answer why there is “water in the fluid“ and why the dipstick never showed the brown fluid I would be very appreciative….especially if you are a Bobcat engineer or master mechanic.

 

[milkman636]

Well, water is heavier than oil. If the dipstick was checked before use, after the tractor was setting a while, you may just have been seeing the clear stuff on top after the water settled. That’s my guess why it wouldn’t have shown on the dipstick, since the dipstick dips the top of the reservoir.

The first question most of us may have is did you stored it indoors or outdoors? And is this the first fluid change you have done? Has it been clear previously?

 

[oldnslo]

Condensation will put water in a reservoir especially if the machine is used till just gets warm and then shut down.

If unit is stored where there are temperature swings and higher humidity that will create condensation unless the reservoir has a desiccant (water absorbing) breather.

Some oil formulations are designed to expedite water separation while others will hold water in suspension longer.

 

[Hoho223]

The tractor has been stored outside all the time. Sometimes under hard cover but mostly under a tarp. I live in NY, mid Hudson valley.
Fluid has been changed at least once. I have 820 hrs on the machine. This isn’t clear because I had problems with the machine and it was at dealer several times. All gratis so I don’t know all what they did.
I understand condensation but that much to spoil the fluid?
Is there another fluid change in my near future?

 

[milkman636]

The tractor has been stored outside all the time. Sometimes under hard cover but mostly under a tarp. I live in NY, mid Hudson valley.
Fluid has been changed at least once. I have 820 hrs on the machine. This isn’t clear because I had problems with the machine and it was at dealer several times. All gratis so I don’t know all what they did.
I understand condensation but that much to spoil the fluid?
Is there another fluid change in my near future?

Tarps are notorious for trapping moisture underneath. Moisture could be condensing on metal under that tarp someplace and finding a path in from the top, Water always find a weakness. Plus every time that reservoir heats up it wants to exhale a little air due to expansion, and as it cools it wants to inhale some air due to contraction. My hope would be that this is just accumulated moisture over time. I'd lose the tarp and probably start siphoning a sample off the bottom in a clear tube periodically to see what was going on. You may have just inspired some fellow owners to adhere more strictly to the hydraulic oil change intervals listed in the manual.

 

[Hoho223]

Have to keep the tarp but will just cover seat area. I live in the woods in NY, mid Hudson valley. Snow in winter and caterpillar droppings in the spring/summer time period.

Still don’t understand why dipstick never showed the contaminated fluid. The dipstick is not flexible and it is short and not as long as the tube to the reservoir but it is the one that came with the tractor.

 

[milkman636]

Have you dipped the dipstick in the old oil to see how the stuff that came out looks on the dipstick?

 

[kthompson]

Look for a split boot on shifter levels or one out of place. Water will easy run down a lever. After your tractor has set for a couple of days pull the drain plug just enough to let the fluid drip if possible. Water is heavier and it should come out first. If there is water in there often you can drain it off that way and often keep the separated oil.
Oh, the trap, sure it does not leak? Some will as they age.

 

[Jubaljohnson]

My question is do you need to clean out the hydraulic chambers of all contaminates

 

[Hoho223]

Have you dipped the dipstick in the old oil to see how the stuff that came out looks on the dipstick?

In effect, yes. I inserted some tubing into the dipstick hole and blew into it (after changing the fluid) and then inserted the dip stick. One could see a very slight tinge of discoloration.