Hydraulic flush

427stingray · Mar 6, 2011

I discovered today my 4270 had the rubber hose that connects the hard tube from the transmission to Hydraulic filter/pump area had come loose. It had sat all winter and apparently had taken a fair amount of rain water in the tube (see photo) . The hydr. dipstick level was correct and still showed good fluid so I don't think it mixed too much. I managed to suction out from the tube below the filter about a quart or two of water until I started hitting hydraulic fluid. As the oil is heavier I want to drain it all out, but is there some way I can flush the system to get any water out ?

suntreemcanic · Mar 8, 2011

Water is heavier than oil, so it should settle to the bottom of the gear case so try draining out some oil and see if any water comes out. Use the hydraulic system for a couple hours and then check the dip stick to see if the oil is milky. That indicates water and oil mixed together. Then you would have to drain the system fill it use it and recheck the dip stick until the oil remains clear.

Elviscaretaker · Mar 8, 2011

I've dealt with a few cars caught in floods in the past. If you know water is in there do not run it. Drain and refill. The oil and water will mix to create a sludge that will stick through out the system, at that point the fun begins. Granted, it may not be the same in a tractor but with most systems pumping around 2600 PSI, it'll mix it just as fast. You should try pulling the plug first either way if it has sat all winter without running and see how much you can get to flow out before hitting just hydraulic fluid. Otherwise, buy a bunch of filters and start flushing.
To flush, drain ..refill.. repeat. If you have access to a transmission power flusher, that may work much better but be careful to not cause any damage.
(check with a local shop)

427stingray · Mar 9, 2011

Ok I re-read my post and I did say "oil heavier than water" . Of course I meant the opposite, sorry for any confusion. So it sounds like there is no way to truly flush the system and only draining and refilling , and maybe repeating is the way. Since I did not run the system I don't think it went to the pump side so hopefully I am ok. I will find out this weekend as the grass is growing in South Texas !

Elviscaretaker · Mar 10, 2011

Let us know how it goes for you. Look at it as getting ahead of the maintenance curve

suntreemcanic · Mar 10, 2011

On larger equipment I have drained the case and flushed diesel through there. It will pick up the water and leave a "oil" coat on everything. You could also open up your gear case everywhere possible and place some sort of heater under it and try to evaporate any moisture left in there. You want to get it out before it has a chance to start rust on unprotected shafts, gears and bearings. After you flush diesel through the case, you would be able to salvage most of the diesel for use in your engine. The water will settle out and you can strain out any dirt.