Translation of hydrostat axle requirements please

[The_Eric]

I'm working on an old Eaton hydrostat for a project mower- looking through the manual, they say:

Quote:
Premium hydraulic oil having a viscosity
equivalent to SAE 20w-20, SAE 30 or SAE
40.
The fluid should be chemically stable, incor-
porating rust and oxidation inhibitors.


What would the correct lube be? Would there be a potentially better option? A local hydro rebuilder says that they recommend a 50w transmission lube in pretty much all hydros. I have some, would it a better option?

If it helps, the mower has a reservoir that is approximately 2 gallons.

 

[The_Eric]

I should amend the original post to say that the hydro rebuiler recommends a 5w50 or 15w15 engine oil. However, I have some 50w transmission oil- would that be better or suitable to use?

 

[George Bynum]

Originally Posted By: The_Eric
I should amend the original post to say that the hydro rebuilder recommends a 5w50 or 15w15 engine oil. However, I have some 50w transmission oil- would that be better or suitable to use?
You're in Iowa ... it gets cold for much of the year. If this is "summer" use only, the low end won't be as critical; 15W40 would be good. If year-round use, the 5W50 will be good, but the high pressure pumps would shear it down relatively quickly. If it were mine, I'd use one of the diesel synthetics, Rotella T6 , Delo 400, Delvac, or similar in 5W40. I'd change it every 100 hours of operation or so.

 

[DriveHard]

Use hydraulic fluid ISO 46 or 68 depending on time of year you will mainly be operating.

I still don't get why people insist on using engine oil in a hydraulic system.

 

[roadrunner1]

The Deere HyGard fits the bill here as its an ISO 46. Its whats specified in my Deere (TuffTorq) axle and I also use it across the board in multiple hydraulic systems.

 

[The_Eric]

Originally Posted By: DriveHard
Use hydraulic fluid ISO 46 or 68 depending on time of year you will mainly be operating.

I still don't get why people insist on using engine oil in a hydraulic system.


I don't either, but after some light reading on some various mowing related forums, I've found the common theme is to use 5w-50 or 15w-50 motor oil. One guy went on to say that the Eaton 851 is a pretty tough unit, unless you run hydraulic oil in it- that it would live nearly forever with motor oil....

Is it because motor oil has more anti wear/EP additives? Is he just way off the reservation?

 

[The_Eric]

I'll add that the cam ring in mine was trashed! Heavily worn. Nothing else though.

 

[DriveHard]

Originally Posted By: The_Eric
Originally Posted By: DriveHard
Use hydraulic fluid ISO 46 or 68 depending on time of year you will mainly be operating.

I still don't get why people insist on using engine oil in a hydraulic system.


I don't either, but after some light reading on some various mowing related forums, I've found the common theme is to use 5w-50 or 15w-50 motor oil. One guy went on to say that the Eaton 851 is a pretty tough unit, unless you run hydraulic oil in it- that it would live nearly forever with motor oil....

Is it because motor oil has more anti wear/EP additives? Is he just way off the reservation?


I am guessing it is because the motor oils you are talking about have a viscosity of a hydraulic oil of ISO 150 or 220 at 40C. Most people who switch to hydraulic oil probably run an ISO 46 or 68...which is at the very low end of what Eaton is suggesting. Most people only mow in the hot summer...and don't do a good job of keeping grass clippings off of their units, and they run hot.

I do know Hydrogear specifies engine oil for some reason as well...maybe I'll ask why.

 

[George Bynum]

For industrial applications, hydraulic oil is undoubtedly the better product. Cold (below 40F, 5C or so) startups are extremely rare so the viscosity grade can be selected for 15 cSt or so at operating temperature without worrying about startup cavitation. Temperatures are usually controlled, so we don't have to worry about it thinning to 6 or 7 cSt. Realize that industrial systems frequently run 24/7/360 ... over 50,000 hours a year. Motor oil is almost always changed in less than 500 hours ... 1% of a year.

It's a tradeoff. I have detractors here ... I like pre-Dexron VI ATF for the excellent (200+) VI. The newest products are just too thin for hydraulic systems ... in the energy conserving emphasis.

I took a quick look on Eaton's and Sundstrand's websites; Eaton recommends 20W20 hydraulic oil, whatever that is. Sunstrand says "Ratings and data for Sauer-Sundstrand products are based on operating with premium hydraulic fluids containing oxidation, rust, and foam inhibitors. These premium fluids include API CD engine oils per SAE J183, Type F automatic transmission fluids, power shift transmission fluids meeting Allison C-3 or Caterpillar TO-2 requirements and certain specialty agriculture tractor fluids."

As for the why, I'm 98% sure it is because there are very few multiviscosity hydraulic fluids.

 

[DriveHard]

Originally Posted By: George Bynum
For industrial applications, hydraulic oil is undoubtedly the better product. Cold (below 40F, 5C or so) startups are extremely rare so the viscosity grade can be selected for 15 cSt or so at operating temperature without worrying about startup cavitation. Temperatures are usually controlled, so we don't have to worry about it thinning to 6 or 7 cSt. Realize that industrial systems frequently run 24/7/360 ... over 50,000 hours a year. Motor oil is almost always changed in less than 500 hours ... 1% of a year.

It's a tradeoff. I have detractors here ... I like pre-Dexron VI ATF for the excellent (200+) VI. The newest products are just too thin for hydraulic systems ... in the energy conserving emphasis.

I took a quick look on Eaton's and Sundstrand's websites; Eaton recommends 20W20 hydraulic oil, whatever that is. Sunstrand says "Ratings and data for Sauer-Sundstrand products are based on operating with premium hydraulic fluids containing oxidation, rust, and foam inhibitors. These premium fluids include API CD engine oils per SAE J183, Type F automatic transmission fluids, power shift transmission fluids meeting Allison C-3 or Caterpillar TO-2 requirements and certain specialty agriculture tractor fluids."

As for the why, I'm 98% sure it is because there are very few multiviscosity hydraulic fluids.


George, we are no longer "Sundstrand" or even "Sauer-Sundstrand" but the manual you are quoting from has changed a little from back in the days we used those names. We are now "Danfoss Power Solutions" and have totally dropped the Sundstrand name. For use in our products we really stress to use a premium anti-wear hydraulic fluid that meets the viscosity requirements for your operating conditions.

I was able to touch base with a Hydro-Gear engineer this morning on why they specify engine oil. The summary to his response is that it is good enough, cheap, and readily available.

If you are using Danfoss Power Solutions components, I can say without a doubt we prefer you run them in premium hydraulic fluid! We use and test with only hydraulic fluid in our labs.

Here is the latest cut from our fluids manual that can be found here:
http://files.danfoss.com/documents/Hydraulic%20Fluids%20and%20Lubricants,%20Technical%20Information/520L0463.pdf

The rated data which we publish in our Technical Information and Service Manuals are based on the use
of premium hydraulic fluids containing oxidation, rust, and foam inhibitors. These fluids must also
possess good thermal and hydrolytic stability to prevent wear erosion, and corrosion of the internal
components. For some applications good anti-wear additives are required.
The following specifications / standards are equivalent to the basic requirements for fluids used in
Danfoss Power Solutions components:
• Hydraulic Oil ISO 11 158 - HM
(Seal compatibility and vane pump wear resistance per DIN 51 524-2 must be met)
• Hydraulic Oil ISO 11 158 - HV
(Seal compatibility and vane pump wear resistance per DIN 51 524-3 must be met)
• Hydraulic Oil DIN 51 524-2 - HLP
• Hydraulic Oil DIN 51 524-3 - HVLP
• Automatic Transmission Fluid ATF A Suffix A (GM)
• Automatic Transmission Fluid Dexron II (GM), which meets Allison C-3 and Caterpillar TO-2 test
• Automatic Transmission Fluid M2C33F and G (Ford)
• Engine oils API Classification SL, SJ (for gasoline engines) and CI-4, CH-4, CG-4, CF-4 and CF (for diesel
engines)
• Super Tractor Oil Universal (STOU) special agricultural tractor fluid

 

[George Bynum]

That's a superb collection of fluids information!

I'd forgotten (if I ever knew) that Sundstrand joined the Sauer Danfoss, now Danfoss, group. We have a Danfoss plant a few miles away (Easley) which has changed products several times; was an SICV manufacturer, Fluid Controls, in the 80's, then, I think, gear pumps, then mobile valves ... your website, like most, chooses to not correlate products with locations. I've not been in it since 1985 or 1986.

Nobody has mentioned my stupid error ... multiplied 24x7x365 for hours in a year ... obviously 24x365.

I've worked with your heavy duty products a good bit; they are solid, reliable, performers. I know nothing of the acquired Hydro-Gear, never dealing with small mobile.

THANKS for the education!

 

[The_Eric]

Thank you guys for all the info!

As another data point, I called the hydro rebuilder I had mentioned earlier- at first they said that genuine Hy-Tran is the best... Period, hands down. I asked why he thought that- he said that some years ago they built a hydro some such and had to provide a warranty. So they had some testing done and the tester concluded that Hy-Tran was the best in all fields. Once I clarified that this just a little hydro (not like that of a combine) and asked why they recommended 5w50 in the little ones, he said because it works and they're not picky. Also that they used the much heavier viscosity to crutch weak or failing units along.

For this mower, I went out and bought a 2 gallon just of Mystik JT5. After looking at the data sheet, the kv100 puts it at about an ISO 68. I'll run that for a little while then drain it and change the filter and then hopefully it will live a long and happy life.


Thanks again!

 

[DriveHard]

Originally Posted By: George Bynum
That's a superb collection of fluids information!

I'd forgotten (if I ever knew) that Sundstrand joined the Sauer Danfoss, now Danfoss, group. We have a Danfoss plant a few miles away (Easley) which has changed products several times; was an SICV manufacturer, Fluid Controls, in the 80's, then, I think, gear pumps, then mobile valves ... your website, like most, chooses to not correlate products with locations. I've not been in it since 1985 or 1986.

Nobody has mentioned my stupid error ... multiplied 24x7x365 for hours in a year ... obviously 24x365.

I've worked with your heavy duty products a good bit; they are solid, reliable, performers. I know nothing of the acquired Hydro-Gear, never dealing with small mobile.

THANKS for the education!


My pleasure. Don't feel bad, I here guys use our old names quite a bit. Even folks who deal with us daily. I have worked here since the Sauer-Danfoss days...but my father has been here since the Sundstrand days.

In Easley we produce mainly our premium proportional spool valves (PVG) product and I think some cartridge valves.