Hydraulic oil recommendations?

[Ljohnsaw]

I have a 1985 vintage Skytrak and the manual states that I should use Hydraulic Oil HD 46. 

When I take a look at Tractor Supply Co. (a place that will actually have hydraulic oil near me), I see Hydraulic Oil ISO 46.  What is that?  Is it safe to use in old equipment (I worry about seals being eaten by new stuff).

They have two brands that seem to be straight hydraulic fluid:

Traveller® All Season Hydraulic Oil ISO 46 at $8/gallon in a 5 gallon bucket
Shell Rotella® Universal Hydraulic Fluid at $12/gallon in a 5 gallon bucket

And N.A.P.A. has either 10W or 30W for $16/gallon!  No mention of HD or ISO.

Since I need about 20 gallons (sprung a leak :(), I don't want to buy the expensive stuff if it is no different than the "store brand".

[BargeMonkey]

 You have to look very close when buying oil from tractor supply, by us they recently replaced the common oil with an oil only suitable in really older stuff like pre -74. The most common hydraulic oil is 32-46-68 "Iso" which is basically the viscosity of the oil. The traveller oil is in a black pail and says hydraulic oil / transmission ? I believe thats the same one we use, try and keep 5-6 in pails for emergency. You should be fine with that stuff, especially if she has a "continued" leak.  ;)

[Brleclaire]

You can use the traveller's hyd oil. It is a mineral based oil that will be compatable with what you got. The shell rotella your talking about is actually hyd/trans fluid that has a viscosity of 10w30. The ISO stands for international standards organization which was began in 1975 to standardize the labeling on goods for international uniformity. Not many hyd oils use the HD designation anymore. I think it stood for high durability which meant it had additives for corrosion resistance and rust inhibitors.

[Ljohnsaw]

Thanks.  The Travelers was hydraulic, not combo hydraulic/transmission.  I have a can of that as the tranny was a little low, too.

The leak is in the steering set up.  I started to see arcs of oil when I was working it hard.  The funny thing is you don't see them right away (clean oil), it has to soak in to the dirt (wet at the moment) or gravel to make a dark streak.  So I inspected the rams for the steering (front and back) - pretty dry/clean, no oil leaks.  So I put them under pressure (hold the steering wheel at end of travel and I hear the pump working hard - no leaks.  Either direction. ??? After another day, I notice some wetness in the cab by the throttle pedal.  One of my lift rams has a seep and there is a little on the "hood" and I figured it was just working its way along.  So I finally said I'm gonna find the sucker.  Cranked hard on the wheel and stretch as far as I can to look under and finally found it (turning left only) but now I need to remove some sheet metal covers to see if its a loose connection (hopefully) or a split hose.

The good thing about an oil leak is it keeps the dust down :D

[Nate379]

10 wt is AW32.

Cheap prices on oil in any case.  I pay about $48 a pail and that is the "buys a crapload of it so he gets a deep discount" price.

I just bought a pail of arctic grade hydraulic oil for my dump truck hoists, that stuff was $50 a gallon.  Pour point of -76*, so should not be too cold blooded like with AW32.

[Ljohnsaw]

Forgot to update.  The hole was just a little pin prick that would send a stream of oil directly down so there was no evidence anywhere on the frame.  Total PIA to remove.  The hose had some of the original Skytrak orange so I'm guessing this was an original hose from 1986.  Stiff like a grapevine!  Forgot the flashlight so working mostly by braille.  What a spider's web of hoses   Had to remove a check valve/Tee combo so it could be pulled free of the frame.  A 60" x 1/2" hose I took to NAPA for a build.  Out the door for $95  :-\  Got the hose back in and put 15 gallons of oil in the tank.  With travel to NAPA (60 min round trip) I was done in 2-1/2 hours.  New hose sure is nice and flexible.