What fluid for custom system?

[matt2491]

I'm putting together a hydraulic system that uses a GM automotive power steering pump to run industrial valves and actuators (one rotator and one cylinder). I've been trying to figure the best fluid to run that will be compatible with all components in this system. Will standard hydraulic fluid upset the automotive p/s pump? Can I run ATF? What would be my best bet?

This is like debating motor oils... but with even more confusion. :laughing:

 

[BrokenTrack]

From what I have heard...but take that for what it is...the BEST hydraulic oil you can buy, is John Deere Hydraulic Oil. Supposedly, due to the antiwear, and antifoaming agents in it, guys who haul with their ton trucks drain the ATF Fluid and put in John Deere Hydraulic Oil for these reasons.

Myself, I do the opposite. I find ATF works really good when it is cold out, and makes my valves respond better, yet the hydraulic coolers keep it within reasonable temperate in the summer. Obviously I do not do this with the newer equipment under warrantee.

ATF/Hydraulic oil is pretty interchangeable so how cold it gets where you live would influence my decision more than anything.

 

[IceStationZebra]

I'm not saying Deere is bad, but I have a hard time believing it is THE best. Everyone is getting base stock and additive packages from the same handful of sources, especially if you are talking about synthetics. For PAO synthetics I've been told there are only a couple suppliers of base stock in the North America. And when you get down to it everything is a compromise - antiwear, viscosity, VI improvers, anti-oxidants, water control, high pressure additives, compatibility with clutch/brake pads, compatibility with copper, etc. What it usually comes down to is what is the best combination for the particular machine and application.

For what its worth IH pioneered "universal tractor oil". Deere's Hy-Gard is a copy of IH Hy-Tran. I have no hard data to say which, if either, is better at this point in time so please don't start a war over which oil is best. These oils have a lot of additives - high pressure for hypoid gears, water absorbing to deal with long storage periods, wet clutch and brake compatibility. Typical hydraulic fluid has none of these and is hydrophobic, allowing water to settle out.

To add to BrokenTrack's comments power steering fluid and ATF will both have a fairly high viscosity index, which means less change in viscosity vs. temperature than hydraulic or universal tractor oil. ATF has a lot of anti-foam, anti-oxidation to deal with the heat and friction pad additives which you don't need. And you didn't mention if the pump is used, but I'm going to assume it is. In this case I'd stick with power steering fluid. It is cheaper than ATF and you don't have to worry about seal compatibility in the pump. Making a major change to the additive package could cause the shaft seal to shrink or swell.

ISZ

 

[matt2491]

Thanks for the helpful info, guys. I'm glad to have found this hydraulics forum to ask questions and share ideas.

What it usually comes down to is what is the best combination for the particular machine and application.

This is exactly the crux of my dilemma. I have a hodge podge mix of different parts in this system. To clarify, I am running a new GM Type II power steering pump. It is feeding a pair of solenoid proportional valves made by Wandfluh. Downstream is an Intermercato RMR3 rigid rotator and a cheap 1x12" DA small cylinder. The valves were $1K each and the rotator was $3.5K, so I really want to be careful not to run something that will upset the seals or whatever in those units. On the other hand, I'm weary about running something that will disagree with the automotive p/s pump. However, the pump is one of the 'cheaper' parts in this system, so I suppose it wouldn't be the worst thing if it became damaged and had to be replaced.

For a while I was thinking about trying Mobil1 Syn ATF, but now that I've learned about JD Hy-Gard and similar fluids, I'm quite curious about that. It sounds like 'performance' hydraulic fluid, and seems like a great fit for the most part, but that's a totally non-scientific gut feeling. It's a bit less expensive than most premium ATFs as well which is nice.

To summarize, here's what comprises my system. All parts are new.

- GM Type II automotive power steering pump


- Wandfluh solenoid proportional valves


- Intermercato RMR3 rigid rotator


- Generic DA cylinder


What would you run?

 

[matt2491]

To add to BrokenTrack's comments power steering fluid and ATF will both have a fairly high viscosity index, which means less change in viscosity vs. temperature than hydraulic or universal tractor oil.

So Hy-Gard and/or other THFs are more suited to a broader range of temperatures than ATF/PSF? For what it's worth, my system will be run outdoors year round in New England. Coldest would probably be around 10°F and hottest around 100°F.

 

[mrmikey]

Dexron 6, synthetic blend would be my choice.........Mike

 

[muddstopper]

I just say what I have seen tried and it works. Years ago the railroad ran rando68 in every piece of equipment they owned. One winter we did a complete change over, hundreds of barrels drained and hundreds of barrels replaced. The fluid used they changed to, DextronIII. The results where a hugh reduction in pump failures. Biggest problem was that tranny fluid would leak when nothing else would. The railroad purchased a suck truck, what everybody called it. It went around everywhere and would suck the tranny fluid out of the equipment tanks and filter it. It had some kind of heater that removed the moisture. Once filtered and dried, the tranny fluid was pumped back into the oil tanks and topped off with new fluid. Is tranny fluid the best oil for a hydraulic system, I cant answer, but I know for a fact it was better than the rando68 and the proof was in the reduction in pump and componet failures. I am pretty sure the railroad specs all their new equipment come with dextron hydraulic oil.

 

[Rich B1]

Mobil 424 or equivalent is a pretty broad range, high end universal hydraulic fluid.

I have 25+ years experience in equipment with Mobil 424....it works

 

[matt2491]

Of course, as with any good debate on fluids, three people offered three different recommendations! :laughing:

All kidding aside, it sounds like I can just about run any decent quality ATF or hydraulic oil as long as the viscosity is in the right range. Factors such as cost and availability may be what ultimately steer me to the right choice.

 

[farm boy00]

Here's my 2 cents from the peanut gallery.

I would try to stay with hydraulic oil because of the expensive parts. But I also do not know much about oils.

Maybe a lighter hydraulic oil.
My family farm and home has 3 types of hydraulic oils from one brand. Winter, summer, and all season hydraulic oil.