We replaced some small filters in the top of the HST pump on my Komatsu D51PX-22 dozer last week and my hand refilled with some water contaminated hydraulic fluid. Couldn't figure out why it wasn't moving properly when we put it back together and then when we were bleeding the system noticed milky fluid, at that time the fluid in the sight glass was milky as well. So now I have a completely contaminated system that I've got to completely flush. I've read the flushing procedures on here but all I've found were dealing with excavators from what I can tell. What would be the best way to flush the HST pump? Also I'm not 100% sure which fluid to be running it it. I have a J20C equivalent but am open to suggestions. Komatsu says their branded oil and I'm having a hard time cross referencing to something I can get locally. Thanks in advance.
IMHO filters of any sort should never be prefilled, that's what filler caps are for. I'd be very surprised if the pump isn't beyond economic repair now. It only takes a few seconds of running like this to achieve.
I have always used diesel for flushing fluid and I keep some clean hyd oil + diesel mix for intermediate flushing. This was from advise of a good hydraulic shop and lots of research reading. Use a filter cart. I have a Parker unit that has 10 micron water absorbing filters and 2 micron polishing filters. I drain and polish my hydraulic oils on a regular basis as PM. You could always add on a kidney loop filter and hope for the best but I would try a complete flush if you put in some really bad oil. Get a cart and clean that system every time you service the machine at the shop. Cleanliness is everything in hydraulics.
He didn't prefilled the filters, he refilled the entire hydraulic tank and 1 of the five gallon buckets had some water in it.
OK
Treemulcher, thanks for the information. I'm not familiar with the filter carts, going to call around and see if I can find someone that rents them. I did see some online for around 4k. Do you hook it onto the hydraulic system somehow or just put the inlet hose onto the tank? The kindney loop you speak of, is this something you just make up yourself. It just adds a temporary filter to the system? If so what filter would you run first s 10 micron water filter? Thanks again for all of your help.
Is it possible there is another separate, issue? You mention ”when you put it back together” Was it just a filter/hydraulic oil change or was other work done? Anecdotal…but we had a Very Large amount of water in a Hitachi Ex270 excavator (new to us) Pumped out oil twice and then fresh oil & ran for two more years. It was in a very remote location on a mountain top so a full & proper repair was impossible…A 20,000h roadbuilder with tagged rebuilt pumps…
BC, Yes it is possible. The reason that we were replacing the small filters in the solenoid valves on the HST pump is I have been having some issues. Something is causing the engine to run hot and at times I have steering problems. I think the hydraulic system has been running in bypass as the outside of the tank will be noticeably warm after a few minutes of operating. I found a guy who has a problem with tracking and the cure was to replace the 2 small filters. I was hoping this was my problem, now since when refilling the hydraulic fluid, at least part of one of the 5 gallon buckets was contaminated with water, I have more issues to resolve.
If I have an accessible port at the base of a hydraulic tank, I install a valve and fitting to match my filter cart hoses, which are #16 FJIC. In my case, #16 JIC male fitting on a shut off valve that normally wears a cap except when connected to the cart. On other systems that don't have a suitable access point, I make up custom suction tubes from PVC pipe with #16 MJIC fitting on one end and drop these into the hydraulic tank to suck the reservoir to empty. I transfer contents into clean 55 gallon drums if I plan to re-use the fluid. Once the contents are in the drum, I can continuously polish the fluid by recirculating the contents of the drum through the filtration cart system for 30-60 minutes. If re-using the fluid, I can pump it back into the reservoir with the cart. I use my cart to filter all of my new hydraulic oils too. Drums will often have contamination even if new. Watch Ebay, Marketplace and auction sites for filter carts. Sometimes they go cheap. Or you can build your own easily enough with the right filters and canisters. A kidney loop filter is just an add on filter that continuously filters a small amount of bypassed fluid through a fine filter set. Pretty easy to build one of these too. I normally use a 2 micron filter unless I think there is water contamination and that type of filter goes down to 10 microns.
You can use a filter cart as a kidney loop filter too if you can tie it into the hyd's. A good hyd. shop is where I rented a filter cart. If you can't tie the filter cart into the system you can still filter the oil multiple times. You can filter the oil then run the machine for several minutes (5-10), shut it off and then pump the oil from the hyd. reservoir through the filter cart again. You can do this as many times as required till you get good clean looking oil that isn't milky looking. If the oil is really milky might need some extra filters for the filter cart. Unfortunately the filters are a little pricey. Still a lot cheaper than new components. The finest filter should be last one the oil goes through. Filter carts generally have 2 large filters.
Hy, gents... From my experience oil and water is a darn mix to get rid off, specially if it turns milky... (hask how i know) But now that the problem is on one´s hand... Water in the Hydraulics, does not behave same as in engine oil... as in the engine all water contamination evaporates into thin air as usually engine oils go to high temps, at least 120ºC , wich is the thereshold for much of the themovalves in the engine oil cooling, if the engine has one. The only harm water will do in your system, besides plugging some small orifices in valves is rust, Rust thats what u can´t have in any HYD system. So i would get it out by draining the system free of the most of that milky solution,(and i would use it as fuel in my cat from 60´s) and then rinse system with diesel by operating the machine at all its functions but unloaded, as water and diesel do not mix well, after overnight u can see the water in botom of reservoir. Then rinse system with cheap oil , like HYD 36/46 , and finally add watever the machine call for HST system. Having some dilution of diesel and cheap oil, will not harm that thing much. (like this u can still use the diesel and HYD oil dilution on your fuel tank) IF it was a Pure HST transmission, well that would call for a complete clean up. But anyway exercise care as HST systems are really tricky, and darn expensive to fix. The cart option, to me is not an option in this job, very hardly u´ll be able to clean that thing... carts where i come from are to empty systems, and store the oil, clean it up before filing again. Or in cases u have a blown out pump with all system with pieces of metal and plastics , then one can clean that with the cart. as some HYD oils are terribly expensive. Good luck
Thanks for the help. Are you saying after draining the contaminated fluid, to fill hydraulic oil tank with diesel and run it? Unloaded meaning just work the cylinders freely, right? Should I try to move the machine while the diesel is in to circulate thru the HST?
I´m not sure how your machine Systems are, u mention (HST) Hydrostat... so i assume GearBox ... so Hydraulic cylinders are not suposed to be on that system, or is not common to be. Systems may share same fluid, but i´m pretty sure they do not share same pump or pumps. But yes what i meant is drain all milky fluid out and get diesel in there, use all systems that use that fluid, drain it next day. diesel does not mix well with water. Then fill system with cheap HYD oil, go through same procedure, drain it, and fill with designated oil. Pretty sure after this u´ll have small system contamination, but free of water. Regarding, Hydrostatics, many equipment use dedicated systems, as the whole system is basically composed of a pump and a motor, pumps and motors. Both variable flow and press, either mechanically controlled or computer controlled. This systems does not go well with rams extending and retracting. Almost pretty sure your Komatsu have a implement pump, control system and actuators. may or may not share same fluid, if it does i foresee a double problem. Let us know and we may help out.
A filter cart would let you drain and flush the system multiple times. It could be used after an initial flush with some diesel added to the hyd. fluid.
Really? I had a worker fill my Bobcat's hydraulic tank with diesel by mistake. Fuel tank same location but other side. I've run easily 75 gallons through it, dump and refilled 2 or 3 times and have been dump and refill every 250hr engine oil change. Still stinks of old "rotten" diesel. My little Hitachi excaexcavator had some weird hydraulic oil that smelled like A/C compressor oil. Was fine till winter hit and it was definitely not cold rated stuff. I've dumped and refilled 3x now (so around 50 gallons) and it still stinks of whatever oil was in there. Dunno why, but I hate that smell, to the point it makes my teeth and sinuses kind of hurt. Same with working on a/c systems.
I don't think you can go by a smell of diesel. Trace amounts of diesel won't hurt anything. If you had a diesel jerry can and it was completely emptied where it wouldn't even drip, it will still have a strong diesel odour.
Smell = still some diesel in the system. Diesel in hydraulics isn't great. Better than water at least but still. I wouldn't put diesel in a hydraulic system purposely. I bought cheap hydraulic oil and used that for flush oil. P66 Megaflow that was like $10 a gallon.
I knew a guy that used to keep spare Vickers hyd. pumps for his P&H excavators in 5 gal. pails of diesel to prevent rusting and contamination. Trace amounts of diesel in a large capacity hyd. system won't cause damage. I'm sure the advice Treemuncher got from a hyd. shop was sound advice.
Sure but putting 5 ir 10.gallons of diesel.... how are you flushing the diesel out so it's only a trace.
Draining the oil and filtering new oil multiple times with a filter cart.
If you can find one even. We had to filter some oil at work and just the filters were a couple hundred $$
Ok ICEHOLE, how would u clean an Hydraulic system with water contamination ? Of course its the cheap and fast solution over here, otherwise we would have said "remove components and clean them". The thing is i have done it, i will have to do it in near future, what i can tell is not an easy job, and if it has multiple rams, it will take ages to get all taraces back to tank. Problem with water is it seats in every corner and it develops rust. Last time i got an hydraulic system flushed was in a JD autotrans, that thing take 120lts of 5€ liter oil. Its unafordable in my planet. Just imagine our friend here with the hydrostat system.