What kind of hydraulic oil do I need for my hydraulic press?

Tom Lewis

Tom Lewis

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Feb 24, 2000
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I have a hydraulic press that I would like to add some oil to. What kind weight, etc. would you recommend?
 
Thanks for the help. I bought the press used 15 plus years ago. I have no idea what kind of hydraulic oil it has. Maybe I should just drain it and put new oil in. I still need to decide what kind of oil to use.
 
Tom Lewis said:
Thanks for the help. I bought the press used 15 plus years ago. I have no idea what kind of hydraulic oil it has. Maybe I should just drain it and put new oil in. I still need to decide what kind of oil to use.
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I'd say it's probably about time for an oil change then Tom. ;)


Edit to add: Most pumps don't specify type of hydraulic fluid to use these days from what I've seen. Although I've seen some recommend Automatic Transmission Fluid. Iso 32, 46 or 68 (Light, Medium, Heavy) should all work. If you're in a really cold climate the lighter may be better, but the heavier is more heat efficient up to a point. I'd probably go with Medium, unless told otherwise.
 
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All oils are noncompressible, which is why you can use just about anything in a hydraulic system...even water, which of course you wouldn't, number one because it has too low a viscosity and number two it would rust out all the innards. ;-) Of most importance is the viscosity and that has more to do with operating temperature than anything else for a press. In New Mexico, I doubt that cold termperatures are going to be much of a concern for you, so a good medium viscosity oil would serve you well. Other considerations beyond viscosity would be detergent oil or nondetergent. Some hydraulic fluids also contain antiwear additives. I don't think you'd need to be too concerned with detergents nor antiwear in a home press.

If it were me, I'd go up to the local autoparts store and just buy a few quarts of ATF (which is a hydraulic fluid)...the press will work just fine.
 
Tony, a hydraulic forging press holds 7-10 gallons of hydraulic oil. In use the oil gets pretty hot. If you didn't have sufficient volume, it would quickly reach the boiling point and all sorts of bad things could happen.
 
Didn't realize we were talking about a forging press. Naturally the OP is going to want to fill to the rated capacity, and not just a few quarts. :) The tractor supply places sell hydraulic fluids in 5 gallon pails for tractor transmissions, which also usually run the front end loaders and power take off. I haven't bought any in about 6 months or so, last time I changed out the oil in the tractor, but if memory serves, I believe I paid around $40 per can for the 'Traveler' brand.
 
Thanks everyone for the help. We have a Tractor Supply store here in town, I will see what they have to offer.
 
Keep in mind that some hydraulic fluids don't play nice with common o-rings and packings, though that usually is only a concern with some of your special application oils or certain aviation hydraulic oils. Stick to a "normal" hydraulic oil (ATF, AW32, ect.) and you'll be ok. The best answer is to replace with the manufacturers recommended oil, but that may not be possible to find out.
P.S. Skydrol is one of those that likes to crack certain packing/o-ring materials. Its been a while since I worked on an aircraft that uses it, so I don't remember off the top of my head which ones it doesn't like.
 
AlaskanHunter is right. Don't put skydrol into a machine that was designed for being used with regular mineral oil. Those usually come with NBR o-rings. They are not capable to be used with skydrol. You would need EPDM o-rings and gaskets for that.
Just drain the whole system, maybe even open up the tank and clean the inside. I would also change the filter.
Depending on the type of pump and how it is mounted you might have to prime it before you can run it again.
Good luck.


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Just like a car, I'd run it and let the oil warm up before you drain it.

Alds good ideas cleaning the tank and changing the filter
 
Most of the "off-the-shelf" and home built presses use Concentric or similar off-brand dual stage pumps such as those sold by Northern Tool and Tractor Supply. Those pumps recommend ATF for all season use. Seems like a no brainer, unless you find you've got some specific pump.
 
Drain the original oil completely for the best results, this may include disconnecting lines and manually jacking the cylinder to it's fully retracted position. A good General purpose oil like Telus 46 is ok. If the press is outside you might want to go to a 32 weight. If concerned about fire, then Water Glycol fluid will work, so will a Qunitolubric, but Quinto is much more expensive and will eventually turn Buna seals soft.
 
Well, actually I haven't. I have a 100 and 25 little giant power hammer that I use most of the time. I don't use the hydraulic press that much. I guess I should go ahead and change the oil.
 
Spammer that revived this thread has been removed.
Carry on.
 
It depends on the application of hydraulic press. Mainly there are three types of hydraulic oil, they are mineral-based, petroleum-based and water based.
Among this petroleum and mineral based are most commonly using type.
For high-pressure application, mineral-based fluid is most commonly using type.
For fire-resistance application, water-based fluid is applicable.
 
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