I probably already know the answer but figured I'd ask the stupid question: Is there any value in running a mild solvent like diesel through the hydraulic system to flush out gunk? I've got a late model Case 580C that had water in the hydraulic fluid. I drained the fluid and followed the flush procedure in the maintenance manual followed by a filter change (and fresh oil, obviously). The machine had several blown seals and sat for a while since then. The current batch of oil looks fine but the last three cylinders I repacked had white gunky stuff behind the piston, presumably from the earlier batch (former owner did 0 maintenance over a period of 10 years). I've got at least four more cylinders to do and am trying to wipe all the gunk out / clean the cylinders as best I can but I got to wondering about running some kind of cheap, relatively thin fluid through the system just to try and flush out all the gunk before putting fresh hydraulic oil back in. Diesel is a bad idea though, right? Thanks!
The hydraulic fluid, besides transferring power through the system, is a lubricant. I do not think any sort of fluid that would flush the system would have very good lubricating properties. I would be afraid the main pump would lock up.
Very bad idea. Nothing should go in a hydraulic reservoir but a good quality hydraulic oil.
Wouldn't worry about cleanliness of system till you finish repacking all your cylinders. You're going to lose and replace fluid with every one you do. When I rescued my C it had buttermilk in the system from sitting and total lack of maintenance. Hydro fluid ain't cheap. There are several threads here about system purge after failure/repair, don't think any one of them involved flushing with diesel. If you let the machine sit for any length of time water will separate and settle to bottom of both sides of reservoir. You can crack/loosen the pipe plugs just enough to let water dribble and will alleviate some of the moisture over time. Over time when reviving my machine I did all the cylinders, suction lines, pump and hoses, removed and flushed cooler so there wasn't much room for water to hide.
Thanks all - that's pretty much what I figured but thought I'd ask. I wasn't going to do it now, but I was thinking about doing it after replacing all the cylinders since my previous "system flush" didn't manage to dislodge all the gunk. I'm doing all the cylinders in one go (along with some hoses), and will then drain the reservoirs and start over fresh.
When I started my hydraulic flush on my 580 SE, the first thing I did was drain the hydraulic tank and I installed a 3/4” gate valve instead of the pipe plug in the bottom. After the flush, I still had a very little bit of water in the oil. When it sits for awhile, I open that valve and out comes a little water, then good oil. I do that most every time I go to start it, believing that one day, no cap full of water will come out. Someday.
If the system is flushed properly there will not be any water left in the system. Quite a while agonI posted how and what works for me when I do them.
I tried a procedure of here for flushing, that was like yours but using a return line and a Rubbermaid trash barrel. With the start up and move certain functions and such. I am confident I got 97% of the emulsified water/oil out but still have a little. All the seals are good but I question if there is water intrusion from somewhere else.
That's what I did too but it still left the thick almost grease like sludge at the bottom of the cylinders. The oil in the reservoir looked clean and the majority of the oil in the cylinder was also clean. For what it's worth, water also gets in via condensation in the reservoir as it breaths. Usually it's a very small amount but over time it adds up. I haven't really looked into it but I know they do make vent dryers - basically just a desiccant that pulls the moisture out of the air before it can make it into the reservoir. That way there is nothing to condense as temp changes.
I had the issue with enough water in the hydraulic oil that during the real cold weather, my loader valve was hard to operate when cold. I did the flush late fall last year and now with the bad seals all replaced, I feel confident going into winter with just the gate valve and trying to drain any remnants of water remaining. I did notice the last couple of seals I replaced, that the brown sludge that was in the cylinders before the flush, is now gone. I think I just need to work the hydraulic system till hot and keep up with the condensation. Problem is, with winter, all I usually use it for is plowing and it never really warms up.
Reread my post and just to clarify, no hydraulic cooler on a C, but did have SHUTTLE cooler off when doing all that other stuff up front and it was flushed. Now back to your regular programming..........