M100 Road Grader - What hydraulic oil to use?

Hello,
Looking for a little info about my road grader...
It's an M100, with a S/N: M-100-216, so I think it is earlier than the "B" series. I'm thinking early 60's, but don't really know.

Was wondering if someone can tell me:
1) what year was it manufactured?
2) what hydraulic oil should be used?

The tank is almost completely empty... only a drop at the end of the dipstick, so I plan to replace the filter, drain whatever fluid is left and refill it. But... I want to use the recommended fluid or a superior one, not just a Universal type and hope it's good enough... I found out the hard way with my tractor that "Universal" is not always as Universal as you hope it is.



Thanks!

I don't know about what fluid to recommend but I will say that is a nice looking grader.

Thanks!

My serial# book would make it a 1963 model. As for hydraulic oil, I think the best listed recommendation I had for hyd. oil was for my Allis Chalmers 816 backhoe loader. It called
for 10W 30 engine oil. That was many years ago but I have since acquired a testing apparatus for metal to metal protection of oils. Along the lines of your opinion I have been
disappointed with hydraulic oils, especially thin grades such as 32 and 46. Operating in moderate to warm climate conditions (if l were to buy hyd. oil) I would only buy hyd. oil 68
as it is a bit thicker. 10W 30 engine oil definitely has better metal to metal protection. In some of my old more worn machines I have even used 30W engine oil in the hyd. system.
I hope this helps.

Years ago we use to use a 10 wt motor oil........ Today, I agree with the other post, I would use a 68 or 100 grade hydraulic oil.

Thanks guys!
So I found my operator manual for it, but it seems very vague to me when I looked up what hydraulic fluid is recommended. It does seem to suggest just 10w oil, but I really want to make sure I use the proper stuff.


Based on that, does it change what either of you would recommend?
Thanks!

Go the the local Farm Store or Auto Store and look at some of the 2.5 gallon or 5 gallon cans of hydraulic oil... I think you will find the C-1 "SPEC" is listed on most.. You will also see the Military spec listed on a lot of them.. The 10wt oil is equivalent to a 68 grade oil .... Look at the "tractor fluid", "HyTrans" , "Universal fluid".... and others.......... I think the C-1 , JD spec, CAT spec, GM spec and others will all be listed on the jug. Most oils meet a dozen different specs.

OOOPS.......... I miss spoke.. the 68 grade oil is more of a 30 wt oil.. The ISO 32 more of a 10 wt oil.. That being said, a standard 32 grade oil might be suited more for a mill or lathe or machine inside a factory... I would look at the can and make SURE it mentions some of the mobile equip specs like the C-1 , or Military spec.. its the addatives that help meet the specs.

That's excellent info... thank you! I found something at Napa auto, that I think may work. It's 10w oil and the back of it says it can be used in equipment calling for C-3 and C-4... I assume that the C-1 rating might just be old, and the C-3/C-4 are just "improved" versions of C-1, or no?

Your quote from the manual puts your initial question in a little different light. When you asked about hydraulic oil in your first post I assumed you meant for running the
"hydraulic system". In general terms a hydraulic transmission usually calls for somewhat thinner oils. That said, for old equipment and the fact that thinner oils give less metal to
metal protection my personal inclination is still to use thicker oils than recommended. As much as there are amazing qualities to Automatic Transmission Fluid the metal to metal
protection is very poor. If you were to only use your grader in the cold of winter the thinner oil is more appropriate. For many of us that run older machines part time, we want
them to last as long as possible without expensive repairs as they don't bring in big revenue for costly rebuilding. This is the reason I go with oils that prolong "longevity". Back in
the sixty's a guy I met had a hydraulic transmission failure in an Allis Chalmes wheel loader. The machine was only two years old but used the 10W oil as recommended. The
dealer fixed the transmission but said to use 20W instead. It ran trouble free for several decades after that.