Hydraulic fluid question

My source is old forklifts that I buy and scrap.
I have a 55 gal. barrel where I put that stuff. I bought that barrel, half full with hydraulic oil, and with a manual pump, for $10.
i

Indeed.
Tractor hydraulics may be very carefree, or not depending on what the hydraulic fluid is doing. Universal Tractor Fluid (UTF) covers most specs at a (adjusted for the price of everything oily going sky-high) reasonable price - but some tractors that are not using it in the transmission can get away with a more boring fluid in the non-transmission hydrualics. Pushing cylinders in and out is less demanding than transmission work.
OTOH, UTF works just fine in boring hydraulics too, and means only one fluid to not get confused about which goes where. It usually does not cost that much more than a more boring fluid, unless you are buying New Holland or John Deere or whatever name-brand overpriced fluid rather than a generic that meets the same specs. Do make sure that any generic you buy meets the specs your equipment calls for, if you didn't build the equipment yourself.
For homebuilds, UTF or ATF or Power Steering Fluid are typical safe choices. If you just need to refill a jack, most anything oily works, but not for long if you don't fix the leak (since you should not have to refill a jack unless you drained it and tore it down.)

I will point out that DOT 5 brake fluid is a silicone oil designed for that purpose and which is hydrophobic - very good property if you are not in the 'freeze" zone

Designed for what purpose? Mixing withanother fluid? Glycol Ester? or Hydrocarbon?
DoNOT do either. DOT 5 is ONLY approved for "clean system" applications.

And even then it better stay sealed. The moisture that does get in likes to settle into the low spots and cause rust. Seen that happen a lot when the stuff first started being a fad item with the rod set.

+1 (I help people chose hydraulic fluids for nuclear power stations)

+ 1 again!

And there are thick hydraulic oils for lower pressure applications like most tractor/farm equipment hydraulics, and thinner ones for high pressure (the 10,000 PSI pumps and cylinders used by Enerpac and others.) My hydraulic crimpers (made by AMP for larger wire sizes -- up to 4/0 -- have (as one option) an electric pump, and that would be quite unhappy with the thick tractor/farm fluid. For that, I wanted to get the Enerpac fluid. As alternatives to that (which has a limit switch at 8600 PSI IIRC), there is a foot pumped one also from AMP (stops building pressure at about the same setting), and I can also use an Enerpac hand pump (which will go all the way to 10,000 PSI) -- it all depends on how many terminals you want to crimp -- and in how confined a space. :-)
Good Luck, DoN.

For that matter -- so will water (where the name "hydraulics" came from, after all. :-) But not for long with most things which are likely to rust. If you want to use water, you want the pumps and cylinders constructed of materials which won't rust or otherwise corrode as a result of being in constant contact with water.
By you -- or by others hired to operate it? :-)
Sound interesting.
:-)
Enjoy, DoN.

"DoN. Nichols" fired this volley in news: snipped-for-privacy@Katana.d-and-d.com:
By me, the terrain, the Florida summer temps, and my son. I only mow my own lawn now, but kept the mower.
It's the nature of these big commercial ZTRs to go FAST. Mow fast, reverse directions fast, turn fast, stop fast. It's a two-stick control, like a tank. It's a 20-acre/day mower.
Because of the way it's rigged, it's possible to slam it in reverse from full speed. Of course, one understands that with hydraulics that just means a very fast deceleration from full to zero, followed by a fast acceleration to full reverse. These are variable-displacement (swash- plate style) pumps; one for left drive and one for right. The rate changes are fast enough that you can hear snubbers unseating, and occasionally will hear the pump belt slip.
It's run like this for 19 years. The only expensive part to replace so far has been the blade clutch. It was a cheezy Bendix Electric part that was not repairable (not meant to be). It lasted eight years, then we switched to an Ogura repairable clutch, and haven't even needed to replace the wear plates yet.
But it gets expensive if something does go wrong. New traction pumps are about $600 each (two), and the traction motors - which _also_ are the rear wheel axles - are about $800 each.
I used to spend - on average - about as much keeping it in good condition as I would per year just on the mortgage for one of those big-box store beer-can mowers. We got about 3 years out of a 'conventional' rider before it was too far gone to repair economically. Anything Murray or MTD has had its hands in is destined to fail early and often.
Now, I generally only replace belts, filters, oils, and one set of blades a year. Something pricey will fail, though... has to!
The point of ALL that was simply that 20W-50 motor oil has held up well for 19 years in an abused hydraulic system that is always running hot.
LLoyd

Some tractors allow SAE 30 etc, but in my experience, 90 weight gear lube worked far better.

I've _never_ in 60+ years seen a tractor manufacturer spec anything as heavy as an equivalent to SAE 90.
Link to the Deere take...note that there is no single industry equivalent standard/spec for transmission/hydraulic oils so each manufacturer has a set of minimum standards of their own. They're all similar, of course...I don't think any modern vendors are using engine oils as their recommendations though other than perhaps the homeowner-class small machines, perhaps for end-user convenience might.
Not to say you might not and probably can "get by", but as others have noted, there's little to be gained by trying to cut corners and potentially much to lose...we buy/use HyGard by the 55-gal drum and Plus-II engine oil in bulk 250-gal delivery for the tractors since it's qualified for the extended change interval it's well worth it (since even the "small" old 4440 takes 18-qt/change, extending from 100 hr to 500 is a big improvement.
If you've got old stuff w/ no warranty concerns, just use a good quality generically branded and you'll be fine if it's of the proper viscosity and wear rating for the application. W/ a $200k tractor, it pays to be in compliance w/ manufacturer's warranty spec's whether they're recommendations are any better than anybody else's or not. :)
--

...
... Missed the link to the engine oil white paper--it's focus is on JD product of course, but there's actually quite a lot of real info in there as well...
--

I have a little Poulan Yard Tractor (Glorified Lawnmower) with the slightly heavier trans-axle. From the HydroGear Manual:
=3D=3D=3D The fluids used in Hydro-Gear=AE products have been carefully selected, and only equivalent, or better products should be substituted.
Typically, an engine oil with a minimum rating of 9 cSt (55 SUS) at 230=B0 F (110=B0 C) and an API classification of SJ/CD is recommended. A 20W-50 engine oil has been selected for use by the factory and is recommended for normal operating temperatures.
Fluid Description Volume 20W-50 engine oil 0.95 gal. (121.6 oz) (3.59 liters) =3D=3D=3D
I know you were mainly disputing the 90wt recommendation but thought you might find what they are putting in the hydrostatic mower trannies of interest...
--=20 Leon Fisk Grand Rapids MI/Zone 5b Remove no.spam for email

Leon Fisk fired this volley in news:jt2ba4$e63$1 @dont-email.me:
yup... even big commercial ones, and even 20 years ago -- and still.
LLoyd

And to confuse things even more, for some reason I don't understand, gear oils and engine oils use a different SAE viscosity scale. The viscosity of SAE 90 gear oil is equivalent to SAE 40 or 50 engine oil.

Yep. This was a Ferguson 30, about 40 years ago. More recently, I helped on a 8N where somone had used 30W in the rear case; but moving to 90 gear oil solved problems.

David Lesher fired this volley in news:jt2nej$t72$2 @reader1.panix.com:
(what's the sound of the buzzer?)... I owned an 8N (1950) for twelve years. Ford changed the gear case/hydraulic recommended oil on that machine in (about) 1995 to a 30W GEAR oil, which equates to about 15W engine oil.
I switched to the new oil at the time of a paint job, and the only thing I had to do to accommodate the lower viscosity was to change the o-rings on the lift cylinder (which on an 8N is only about a half-hour job).
LLoyd

...
Acutally I specifically mentioned I could believe that for the application...you won't find it recommended for one of these, though...
BTW, it's not as green outside here nor are ours this shiny any more...
:)