I am working to get a system cleaned up. I think mainly this boom lift sat idle too long with a low hydro tank and took on some water. Oil was milky so what was in it was dropped. It is a 36gal system, oil was dropped from the tank, and replaced with 30gal of clean oil so far. Cheap oil mind you because I am not yet sure if it will clean up without another oil change. I would like to introduce a desiccant. I was recently reading on a few methods. I understand physics well so some of this does not seem practical, like drawing a strong vacuum on a hydro tank that was never designed for that. I am hoping I can swap wicking filters a few times and get to reasonable water content. Crap, I should mention the only filter on it is a screw on return side bypass filter.
Yep, I recommend Zinga Aqua-Zorb if it has a spin on filter head OR you can install a return filter head inline, using a couple hoses to remote it if necessary. They make a couple different style filters identical to Gresen and I don't remember, Parker maybe? In 3 and 10 micron. For example: https://www.zinga.com/products/spin-on-filters/spin-on-filter-elements-se-le-series/
We use water absorbing filters on a filter cart and they work surprisingly well.
There was a discussion on this forum a year or more ago where there was a video showing a buggy that used vacuum and filters to remove water. The mechanic in the video mentioned he was renting the unit for that job. I made inquiries about purchasing a unit but didn't have a spare $10,000 laying around for the small unit. They were using a big unit. I can't find my notes nor the video. If someone here remembers that conversation, I think it might be helpful.
There's some noise about those carts here . But I thought there was a video too, I'm not finding it yet. Or I am, try here . Edit- I did find some more, searching for hydraulic filter cart.
Parker Micro-Glass water absorbing filters @ 10 microns (or their equivalent from Napa) is what I use in my filtration cart for water removal from any questionable systems. I usually do a final polish with a 2 micron filter before reinstallation of the oil. If I had a system go milky, I would certainly want an on-board kidney loop system installed until it was cleaned up good. Bypass filtration is just good insurance anyways and I run these on several of my engine and hydraulic systems. I have several Filtration Solutions units mounted direct on equipment.
The second link is the one I was talking about. I called on a price for the cart used in the video and about filters. The filters would work OK on a small amount of water but they only take out a little bit at a time. Stripping a lot of water out of a system might take a bunch of filter changes. Just changing the oil was less expensive than continually changing oil filters. What I wasn't able to find out is the percentage of water in the oil that it takes to turn hydraulic oil milky. If we are talking a pint per gallon in a 50 gallon system that estimates out at 6.25 gallons. The filters I asked about would only strip out about half a pint at best before plugging up as I recall and they cost around $40 each. That appears to me to be 8 filters per gallon so $480 of filters per each gallon removed. The only thing that made sense was that cart in the video and I couldn't make that pencil out either. My conclusion was the filters make sense when you open the fill cap and find the white sludge on the bottom of the cap but the oil hasn't changed color or gone cloudy yet. If it had gone cloudy, it was cost efficient to change it a couple of times and then try the filters. The most cost effective way was to just not let water get into the system. If the machine was only a runner and not used to make a living with, change the oil once and just keep on keeping on. I have found that in occasional use, an old machine will run for a long time before something sticks.
There was also a mention in a thread that some oils shouldn't be filtered below a certain micron. I think it was 4 micron but not sure or which oils it applied to. I was in a warehouse for a place that liquidates business assets. They had a Parker filter cart for $1000 or $1400 that if I was in the business would have bought. I think it was about 1/2 price of new. Donaldson has lots of filters but some cost close to $100 Cad. Better filter carts have a gauge(s) on them (vacuum?) that gives you an idea when the filters need replacing.
I usually look at is from a what's this piece of equipment, junk, ****, really worth. Specialty filters and/or cart rental adds up quick. A few flush and dumps with hose store bucket oil may be more cost and time effective. This is why I'm so on people about keeping up on their filler/breather caps too.