Fluid to use? Hyd.

[Bob Rooks]

Some simplified hydraulic oil questions answered here:
Choosing the Right Hydraulic Fluid

He forgot to mention Thermal Equilibrium.

 

[Wayne County Hose]

Some simplified hydraulic oil questions answered here:
Choosing the Right Hydraulic Fluid

He forgot to mention Thermal Equilibrium.

Stay away from advice by him. He is the self proclaimed "king of internet hydraulics." There is an article he wrote in last months issue of that mag that is seriously flawed. It was about double acting cylinders and how if you removed the piston seals the cylinder still would not drift. On paper, he is correct, in the real world, he was dead wrong.

 

[Diamondpilot]

My neighbor runs ATF in his Bob-Cat. I also see guys run it in the snow plow pumps. They like it because it is easy to get your hands on in the middle of the night if they blow a line. It also show up great on snow if there is a leak.

Chris

 

[Bob Rooks]

If you do a "hydraulic oil" search here you will get the straight story, and you can pretty much believe what they have to say. At least I do.

D4174-89(1999) Standard Practice for Cleaning, Flushing, and Purification of Petroleum Fluid <FONT COLOR=RED><B> HYDRAULIC</B></FONT> Systems

 

[geobar]

I run Dexron in my 2004 Jinma 284, and find that it performs better then it did new with no drawbacks so far. Be careful though because atf and hydraulic fluid do not mix. You will need a complete flush to make it permanent on the atf. My 2004 hyd system was filled with motor oil from the factory and atf will mix with that so I did not have a flush situation. I flushed and switched my snow plow to atf because hydraulic fluid absorbs moisture from the air and I kept getting ice in the system at the start of every winter. IMO atf flows, lubricates, inhibits rust better and keeps the system cleaner.

 

[Red55]

Wow geobar didn't know that about hydraulic fluid absorbing water. My MTD 22ton log splitter specifies atf and was thinking of switching it over to hydraulic fluid- now I'm not thanks Ed

 

[RonMar]

Wow geobar didn't know that about hydraulic fluid absorbing water. My MTD 22ton log splitter specifies atf and was thinking of switching it over to hydraulic fluid- now I'm not thanks Ed

Yep, it will absorb and eventullay emulsify. I recall reading somewhere that it takes around 200-300 PPM of water to start to be visible. The water typically gets into the system thru the resovoir tank breather. You shut down your hot machine and as it cools, the air in the tank contracts and fresh air containing moisture is drawn into the resovoir. The moisture condenses on the interior walls and mixes with the fluid.

They make dessicant air breathers that absorb this moisture and help keep the tank dryer. I have made my own using a cheap clear inline fuel filter with one side filled with indicating dessicant. When it is blue it is dry, when it turns pink, it is saturated with moisture. I dump out the pink dessicant into a glass bowl and microwave it. This releases the moisture and returns the dessicant to it's dry indigo blue color. I put it back into the filter and re-install it on the breather vent. I have one on the tractor and one on the backhoe resovoir vents.

 

[Red55]

Thanks Ronmar- Too early for me to switch to synthetic hydraulic but is that any better with moisture being absorbed. I do remember about someone posting about using a gas filter to keep dirt out of the system. Did you post about your filter? Thanks Ed

 

[Bob Rooks]

.....because hydraulic fluid absorbs moisture from the air and I kept getting ice in the system at the start of every winter.

I think the American Petroleum Institute (API) would be interested in your findings. Why not submit a paper?

 

[Wayne County Hose]

?????????????? You guys worry too much. There are millions of pieces of equipment worldwide running hydraulic oil and have no moisture issues. If you're that worried, dump in a 99 cent can of isopropyl. If you do have moisture issues, you don't change your hyd oil enough anyway.