Hydraulic/Hydrostatic Oil/Fluids?

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rkcarguy
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Hydraulic/Hydrostatic Oil/Fluids?

Post by rkcarguy » Fri Jan 18, 2019 5:12 pm

Most of the specs I'm reading online for the hydraulic motors and pumps call out fairly basic SUS (viscousity range) requirements for hydraulic oil/fluid.
Any particular product that is preferred?

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warmstrong1955
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Re: Hydraulic/Hydrostatic Oil/Fluids?

Post by warmstrong1955 » Fri Jan 18, 2019 5:37 pm

Oils with more anti-wear additives are better.
Motor oils have more anti-wear components than AW hydraulic oils, and tractor hydraulic fluids.
Because of the increased life motor oils provide, that's what I have used for many years.
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Re: Hydraulic/Hydrostatic Oil/Fluids?

Post by John Hasler » Fri Jan 18, 2019 7:51 pm

Many of the additives in motor oil are there to deal with products of combustion and so are useless in hydraulic systems. Many useful additives cannot be used in motor oil due to EPA regulations that do not apply to hydraulic oil. Motor oils are also optimized for high temperature operation and low ash.

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Re: Hydraulic/Hydrostatic Oil/Fluids?

Post by warmstrong1955 » Fri Jan 18, 2019 8:01 pm

John Hasler wrote:
Fri Jan 18, 2019 7:51 pm
Many of the additives in motor oil are there to deal with products of combustion and so are useless in hydraulic systems. Many useful additives cannot be used in motor oil due to EPA regulations that do not apply to hydraulic oil. Motor oils are also optimized for high temperature operation and low ash.
That's why motor oils cost more. More goodies.
In spite of what additives are in it, that you don't need, there are more that are above and beyond what AW hydraulic oils have to offer.
It's also one reason why most underground mines use motor oils in the hydraulic systems of their equipment. And with better results than AW oils.
For light duty applications, motor oil may not be necessary. And, again, it costs more. As far as anti-wear capabilities, it is superior.
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warmstrong1955
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Re: Hydraulic/Hydrostatic Oil/Fluids?

Post by warmstrong1955 » Fri Jan 18, 2019 8:03 pm

FYI....it also works better than ATF', C3 types, AW's, and TDH's in power-shift transmissions.
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Re: Hydraulic/Hydrostatic Oil/Fluids?

Post by BigDumbDinosaur » Sat Jan 19, 2019 12:41 am

rkcarguy wrote:
Fri Jan 18, 2019 5:12 pm
Most of the specs I'm reading online for the hydraulic motors and pumps call out fairly basic SUS (viscousity range) requirements for hydraulic oil/fluid. Any particular product that is preferred?
In most cases, a quality motor oil is suitable. In my F7, I use 10W-30, the same as I use in my automobile. Although some additives in motor oil are present to deal with the effects of combustion blowby and hence are of limited value in a hydraulic system, most additives are viscosity modifiers, foaming inhibitors and detergents that promote general system cleanliness, all of which will help prolong the life of your investment.

Along with using a quality oil, I recommend you provide adequate filtration on both the pump inlet and the return line to the reservoir. Your reservoir should be fitted with a suction strainer, such as this one, to prevent the pump from ingesting particulate debris. A 10 micron (or better) filter, such as this one, should be in the return line to trap contaminants that are the natural result of wear in the pump and motors.

The oil in any hydrostatic system should be changed at least once per year, regardless of how little or how much the system is used. Oil gradually oxidizes and breaks down due to exposure to the atmosphere, and the additives likewise break down over time. The return line filter should be replaced when the oil is changed. Changing the oil and filter is a lot cheaper than replacing a damaged pump!
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Re: Hydraulic/Hydrostatic Oil/Fluids?

Post by John Hasler » Sat Jan 19, 2019 9:57 am

BigDumbDinosaur writes:
Although some additives in motor oil are present to deal with the effects of combustion blowby and hence are of limited value in a hydraulic system, most additives are viscosity modifiers, foaming inhibitors and detergents that promote general system cleanliness...

But due to EPA regulations the manufacturers of motor oil for automobiles are no longer able to use the best of those.

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warmstrong1955
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Re: Hydraulic/Hydrostatic Oil/Fluids?

Post by warmstrong1955 » Sat Jan 19, 2019 12:43 pm

The only AW additive in motor oils I remember the EPA going after, was ZDDP. I think it was mostly due to the phosphorus in it, as it damaged catalytic converters. I think it happened sometime in the 90's. Many motor oils still have it, but only in some API codes, and they cut down the amount used to about a third of what was previously used.

Were there others John? With the EPA involved.....probably, but I'm unaware of others in motor oils.
I know of some changes in gear oils, and I have some ugly stories back when Dexron was replaced by Dexron II.
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Re: Hydraulic/Hydrostatic Oil/Fluids?

Post by John Hasler » Sat Jan 19, 2019 2:41 pm

They also object to zinc and sulfur.

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Re: Hydraulic/Hydrostatic Oil/Fluids?

Post by warmstrong1955 » Sat Jan 19, 2019 3:35 pm

John Hasler wrote:
Sat Jan 19, 2019 2:41 pm
They also object to zinc and sulfur.
The 'Z', in ZDDP is zinc, (zinc dithiophosphate....if I spelled that right) but I their primary whine if I remember, was the 'P' phosphate part.
Sulfur, and lead.....are known enemies of the EPA Gods. The old SCL type EP gear oils got on the hit list years ago. Smelly black stuff, that was the standard for limited slip diff's in heavy equipment, and autos as well. They killed the oil before there was a workable replacement. Good thing the Detroit Locker came around.....
Sulfur messes up catalytic purifiers better than most things.....and why all the new diesel fuels have max sulfur content, mandated of course, by our friendly EPA. The only place I remember a major problem with sulfur in diesel fuel, was in Greece, and was all because of failures with ECS purifiers. They were actually disintegrating in our mining equipment.
That's worldwide. Greece was the exception. So sulfur is a problem....I suppose so....but a major problem.....I didn't see it.
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Re: Hydraulic/Hydrostatic Oil/Fluids?

Post by rkcarguy » Sat Jan 19, 2019 4:37 pm

I kind of wondered about all that, if motor oil is the way to go I think I'm set. I've been through the school of broken engines in kart racing after the EPA removed most, if not all of the zinc, phosphorous, and sulfur from the oil I'd been using. I had to go to Maxima's 4T motorcycle oil to find something with a good additive package that was readily available. Mobile-1 full synthetic automotive oil might as well have been turned into bath water.
I had a relative with a motorcycle shop (now retired), so I ordered Maxima by the case before that and have a lot on hand in 5W-30, 10W-30, and 10W-40. It has almost as much zinc as Amsoil, so to stretch it a bit in normal use I usually use about half of it and half of some off the shelf automotive oil like in my truck for instance. My boat, race kart, motorcycle, and other hard working applications get the full dose. The motorcycle redlines at 13,500 and the Maxima has a wonderful anti-foaming package to help it hold up to RPM's like that in addition to the additives.
The difference is notable, the V10 in the truck is now quieter and I recorded a .8 mpg improvement, quite a bit when it only gets 8-11mpg. In kart racing I went from 3 motors a season to 3 seasons a motor +. For newer cars where everything is roller rockers, cams, and such, its not really needed. Anything flat tappet or cam over bucket will appreciate the additives on the rubbing surfaces.

Might a blend of good motor oil and ATF be the ticket?

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warmstrong1955
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Re: Hydraulic/Hydrostatic Oil/Fluids?

Post by warmstrong1955 » Sat Jan 19, 2019 5:06 pm

I would avoid ATF's like the plague. In a application that is designed around a particular ATF....yup....use it, but other uses, take care. Extreme care.
There are, and can be problems with coefficients of friction,ie; type F's vs Dexron, and seal compatibility. ie; Dexron & Dex/Merc with Viton seals. I have a Duramax and I have to be careful which Dex/Merc I use. The Allison trans was designed around Dexron III....which you can no longer get. Some brands of Dex/Merc, the replacement, are compatible with the Viton seals....most are not.

What I understood, is the old ZDDP oils were more important with flat tappet engines. No doubt why they worked so well with swash plate piston hydraulic pumps, and even gear pumps. They make ZDDP additives, but with a hydraulic system, I wouldn't mess with it. I think the modern motor oil AW additives are not only sufficient, but are still superior to AW hydraulic oils. My opinion is based on maintenance history.
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