Hydraulic fluids... what's the deal?

[vhol5]

Hey hydraulic gurus! Why are there so many different types of hydraulic fluids? What happens if you use the wrong one? For example, you have a hydraulic pump needing fluid, and there's no label specifying the type to use. Is there more of a general purpose one?
Thanks for any info!

 

[klitzke]

Really you can put just about any fluid through it! Of course that's the redneck way and you may or may not regret it... If you know what kind of material the pump is made of, you can rule out certain fluids.

Your local hardware/farming supply store ought to have pretty decent fluid that runs through lawn mowers and tractors. It's usually not terribly expensive and will do the job well.

Depending on the motor strength and size of the internal orifices, you may want a thinner or heavier fluid.

Happy hunting!

 

[crewchief888]

not nearly enough info for me to even make a guess.

you talking about a log splitter?

or a hydrostatic drive mower?
tractor with a loader?

extreme temps?

they all use different grades of oil.

 

[brownbagg]

most of its just green, biodegradable, safe for the environment

 

[KEH]

Some different makes of hydraulic oil don't mix well. I used two different brands once and the oil foamed. When used separately either one worked fine.

Use what ever is called for in hydraulic jacks. Back in the day I put some brake fluid in a hydraulic jack and it messed up the seals.

KEH

 

[Aquaticbob]

I've found most of the hydraulics I've used use dexron 3 ATF. However those are hydraulics for lifts and presses

 

[jdieter]

Not sure if the op is talking about ATF or plain hydraulic fluids. Regarding hydraulic fluids there are 2 basic types mineral oil based and synthetic, the latter with a higher flash point for high temp applications to reduce fire risk. Viscosity is the primary parameter for hydraulic oils, from there you go to additives for anti-wear, corrosion resistance, extreme pressure. The systems ambient temp, operating temp and general design determine the most appropriate hydraulic oil spec. for efficient long term operation. Unlike engine oils that have to deal with combustion by-products, hydraulic oils have an infinite life with the proper temperature and filtration design. I don't know how closely hydraulic fluids and ATF's align, maybe somebody can enlighten us. My pre-retirement experience in a heavy industry only covered hydraulic fluids.

 

[Diesel Dan]

There are fire resistant hydraulic fluids that don't mix well with regular fluids as well.
A lot has to due with the additive package, you need the right fluid in a hydrostatic transmission. A simple bottle jack will function on a lot of different stuff.

 

[GYPSY400]

Hey hydraulic gurus! Why are there so many different types of hydraulic fluids? What happens if you use the wrong one? For example, you have a hydraulic pump needing fluid, and there's no label specifying the type to use. Is there more of a general purpose one?
Thanks for any info!

It all depends on what you are filling.. a simple system like a wood splitter can use engine oil or A TF... more complex stuff like hydrostatic drives need specific fluid... please explain what you are going to put it in.

Sent from my SGH-I747M using Tapatalk

 

[sasky]

It's all little different. Until 04 ish all Deere combines used low viscosity hydro. Now just regular. Tractors all use plain old hydraulic oil. Deere sprayers use 10w-30 engine oil. Augers with movers use atf it's a good all season oil for that application

 

[vhol5]

not nearly enough info for me to even make a guess.

you talking about a log splitter?

or a hydrostatic drive mower?
tractor with a loader?

extreme temps?

they all use different grades of oil.

This was just a general question, that's why i was so vague.

Actally, I acquired a hydraulic pump and motor. No oil info. Don't know what I may build with it...

 

[vhol5]

Not sure if the op is talking about ATF or plain hydraulic fluids. Regarding hydraulic fluids there are 2 basic types mineral oil based and synthetic, the latter with a higher flash point for high temp applications to reduce fire risk. Viscosity is the primary parameter for hydraulic oils, from there you go to additives for anti-wear, corrosion resistance, extreme pressure. The systems ambient temp, operating temp and general design determine the most appropriate hydraulic oil spec. for efficient long term operation. Unlike engine oils that have to deal with combustion by-products, hydraulic oils have an infinite life with the proper temperature and filtration design. I don't know how closely hydraulic fluids and ATF's align, maybe somebody can enlighten us. My pre-retirement experience in a heavy industry only covered hydraulic fluids.

Good general info!

 

[jdieter]

This was just a general question, that's why i was so vague.

Actally, I acquired a hydraulic pump and motor. No oil info. Don't know what I may build with it...

I would do some research on the pump to find it's oil spec. If that's a dead end determine the type of pump, vane or gear most likely. Then make a guess at the displacement based on the physical size and port size. From there find a pump manufacturers spec's for a close match to yours, maybe somebody like Vickers.

 

[Spudland_Dave]

It's all little different. Until 04 ish all Deere combines used low viscosity hydro. Now just regular. Tractors all use plain old hydraulic oil. Deere sprayers use 10w-30 engine oil. Augers with movers use atf it's a good all season oil for that application

Umm, not quite 100% right...Heres a link from the 9770 manual dated 09:
http://manuals.deere.com/omview/OMHXE13769_19/OUO6075_0000091_19_05MAY08_1.htm
Old machines were typically all normal HyGard, only substitute when cold weather dictates. Same for tractors and most of all the Green Fleet.


And contrary to popular belief Hydraulic oil isn't just slippery stuff in a pail. MFG's spec out different specs and engineer products around those specs.
Back in the day there was a big problem with New Generation Deere's with no brakes. The issue was those guy were running HyTran (IH) fluids in their beloved Green Machines...what the difference & problem was was HyTran was formulated to keep Water in suspension, HyGard was formulated to drop water out of suspension. The glue Deere was using to hold the pads to the backing plates was a water soluble type glue and when the water contaminated it, voila...Bye-Bye brakes.

Dad tried to cheap out one and put HyTran in his Kubota GST...talk about F-ing it up, shifted like ****, made all sorts of noise, drained it and re-filled with UDT (Kubota's name for hydraulic Oil) and voila...the world was at peace once again.

Hard to say what you need...If you've wondering about something "simple" like a Hydraulic Wood Splitter or such, then yeah, anything will probably be fine. If you're talking about a complex system with a common sump...go with OEM oils.

 

[sberry]

A pump like a log splitter can use common hyd fluid, things with a driveline call for hydraulic transmission fluid. A hydrauilic jack uses an extreme pressure fluid,,, as I recall in the 10K range. Hytrans about 2500-3500

 

[Kracin]

well you could have a few different types of hydraulic oil depending on the base of it (pretrolium based, etc) and then theres temperature factors, a guy who starts a tractor in -10 degree weather might not want to wait a half hour to start using it, some hydraulic oils will let you run right off the bat, some wont depending on the chemical makeup.

then theres extreme heats, fire resistance. compatability with the type of pump and seal types, etc.

 

[Spareparts]

Generally with a pump and running a cylinder like a log splitter or press with a pressure around 3000psi AW32 will work fine. Running hydrostatic systems sometimes require different weights or additives. I run the AW 32 oil in roll off truck, fork lifts, tractors, trash compactors and bailers without a problem.

When I first started hyd. oil was about $2.00 a gallon now it is around $11.00 and up. The more elaborate oils will be more expensive, If your pump is a gear or vane type AW 32 will work but if a piston or variable type then you need to do some research. Hope this helps.

 

[sasky]

I am not seeing what I was wrong about. I guess you can use low vis in a newer combine but I would never think there would ever be a day I would need to.

 

[fteufert]

What fluid for a 25 year old Craftsman 2 1/4 ton floor jack?

 

[Spareparts]

Jack Oil.

 

[vhol5]

Jack Oil.