Tractor in pond--water in hydraulic oil

DWCox · Oct 2, 2009

I was backing my John Deere 790 tractor up to the edge of the pond and ended up in so that water was half way up the entire tractor. After some work, I managed to get out. I checked my engine oil and it looks fine (though I will change it anyway). The hydraulic oil, however, definitely has that milky look and I had changed it and replaced the filter only 80 hrs ago.

What is the best way to purge all moisture from a hydraulic system? Do I have to do it multiple times, which could start to get pricey--or flush it with some other product first? I have the standard FEL and three point system hitch. Oh yea, since the front axle was under water, I am definitely dumping that fluid and replacing it as well.

Thanks in advance!

Darrel Cox

sandman2234 · Oct 2, 2009

Sounds like an expensive dip in the pond. Kind of like falling in with your wallet still in your pocket and everything getting wet, including things like your cell phone, etc in todays age.
As far as drying out the hydraulics, I can't really help, as I haven't had any real experience with it, but wonder if changing the fluid and leaving it to drip dry completely before putting the drain plug back in. Also might help to put it in the garage or shop during this and crank the heat up so that the room temp is way too hot for comfort. Might aid in evaporation of the water left in the system, not sure, but it can't hurt as long as you don't burn the house down. Good luck!
David from jax

valley · Oct 2, 2009

You could drain the fluid, fill with diesel fuel work it till the fluid is warm and drain it. I did mine that way and was surprised how much gunk came out.

dex3361 · Oct 2, 2009

valley said:
You could drain the fluid, fill with diesel fuel work it till the fluid is warm and drain it. I did mine that way and was surprised how much gunk came out.

I am not familiar with that tractor but if it is a HST I don't think that I would do that it could score the Swash plates in the HST pump and motor from lack of lubrication. Just a warning.

powerstroke444e · Oct 2, 2009

I would drain it right away and change the filter, every minute the water is in the oil it does more damage to your machine. Also drain all the lines that you can. After changing the oil I would run it @ operating temp & keep a close I on the fluid to make sure it don't get milky. I would change the filter several times. When the oil get to operating temp it will help get the moisture out of the system that did not drain, you may have to change it twice.
As far as long term affects I wouldn't get to worried as long as you get it drained soon.
The school of hard knocks is not cheap but it is the best teacher.

IslandTractor · Oct 3, 2009

I haven't had experience with this issue but wonder why you couldn't drain your hydraulic fluid, run it through a water trap of some sort and then reuse it. Water should not be hard to remove from oil and so the oil should be able to be reused once the water separates.

J_J · Oct 3, 2009

It is not that easy to recover the original fluid from a mix of hyd fluid and water. If the water has been emulsified/blended, I don't think it is worth the effort. There are filter machines that can do it, but they are expensive. Most hyd fluid and motor oils have detergents in them, and that is why the oil is emulsified. If water were to get into non-detergent oil, it would go to the bottom of the container, and could be removed easily.

bp fick · Oct 3, 2009

Accidents happen. The answer here is to drain the systems. Completely.

New filters as well. Check everything after another hour of operation. If you have the slightest doubt, do it again!!

Better to use Mystic or other "house brand" fluids and change everything, twice if need be, then to do nothing, or to try to do something like water recovery with home equipment. If cost is a consideration, house brand fluid, that meets your manufacturers specs. The cost of transmission repair or replacement just isn't worth the risk. Consider the cost of the fluid and time as penance.

DWCox · Oct 3, 2009

Thanks so much for the answers. Believe it or not, I am counting myself quite blessed that it did get into the engine oil.

Diamondpilot · Oct 3, 2009

Do as the others said. Change the fluid out 2 times minimum. $250 in fluid and filters is a cheap price to pay for your mistake. You could have lost the whole tractor. Chalk it up to a learning experience.

Chris