hey johnnyb,
sorry i didn't see this one.
water in the hydraulic?
so my first questions would be to ask what does the engine oil look like? is it the correct level? and the same with the coolant. does this unit sit outside?
have you been having to adjust any of those levels?
the only other suggestion is to check the breather/dipstick cap on the hydraulic tank, make sure it is sealing good when you put it back on, no cracks in it, the usual stuff like that.
Even in cold weather you shouldn't see any water/moisture in the hydraulic oil at all. If there is enough to make the oil get milky you have to be getting water in it from somewhere.