Civilian hydraulic oil for cab lift reservoir?

What are you guys using as hydraulic fluid for the cab lift reservoir?

The manual specifies "MIL-H-5606 (OHA): Hydraulic fluid, petroleum base, aircraft, missile, and ordnance". I called Autozone and asked for some missile oil... no dice. (I'm kidding.)

I found this spec sheet and then found the C-635 spec and it translated to Chrysler fluid...

Wouldn't it be the top line then? H-515?

Sorry I can't answer your question about the H-515. I bought the Mopar stuff and it seems to work fine. If you find out it is NOT correct for me to use C-635, please let me know and I will drain mine and get the H-515 spec stuff (if I can find it).

Ok. In your chart, the fluid I'm wanting to replace is the top line (OHA), for which it says H-515 is the NATO equivalent. The C-635 you're using is an equivalent replacement for a totally different fluid, on another line of your chart. It may be a totally fine substitution, or it could be catastrophic... sometimes these fluids require different seal materials or the fluid will eat them.

I just use regular hyd fluid. I have a can of the mil stuff somewhere if I can find it tomorrow I will add a pic.

Like Suprman said, on the few I've been around, we've just used regular hyd oil.

I honestly think just about any oil would work on such a simple hyd system.

Ok, thanks. I'm just trying to be careful - I don't want to put something wrong in, and have to tear the whole system apart.

I've designed a lot of aircraft systems that use MIL-H-5606 (or MIL-PRF-5606H). It's often called "red fluid" in aviation. I've used it a lot. It's pretty good stuff. It shouldn't be hard to find at all.

http://www.aircraftspruce.com/catalog/lgpages/phillips66XC5606H.php?clickkey=43943

http://www.aircraftspruce.com/catalog/lgpages/hydfluid5606qt.php

In a lot of applications they have switched over to the more fire resistant MIL-PRF-87257 b. It's completely compatible with 5606. I'm always careful when working with them, but in reality, they are pretty inert. As listed above, the main problem with swapping out fluids is seal compatibility.

The systems on these trucks are so super simple that you can probably use other fluid without much risk.

Michael

This was all they had at NAPA. Think it will work?

Awesomeness said:

This was all they had at NAPA. Think it will work?
View attachment 623287

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Yes.

The only thing you may run into is it not mixing well with whatever is already in there. May want to drain the whole system and refill. I've always just added regular hyd oil to what was already in there without problems but you never know.

I also use generic "Tractor Fluid" in mine. It costs for 5 gallons what some special fluids cost for a quart. No issues after about a year. A suggestion, suck out some of the fluid from the fill hole and check it out. Mine was milky from water, plus some rust. If you will suck out as much as possible (or could loosen a lift cylinder hose, and activate lift) and then fill with new fluid. Do that every few months and soon the fluid will look nice and clean as it should.

My pump unit has no cover over it so I think temp changes and rain cause water to get sucked in. Does your pump unit have a cover?

Awesomeness said:

What are you guys using as hydraulic fluid for the cab lift reservoir?

The manual specifies "MIL-H-5606 (OHA): Hydraulic fluid, petroleum base, aircraft, missile, and ordnance". I called Autozone and asked for some missile oil... no dice. (I'm kidding.)

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SAE 10. Mineral base non detergent.

tennmogger said:

Does your pump unit have a cover?

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Yes, mine has a cover.

That looks like some nasty stuff according to the label, but then again, who drinks hydraulic fluid!!

ATF works well.

tennmogger said:

My pump unit has no cover over it so I think temp changes and rain cause water to get sucked in.

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After rebuilding my HPU, I left the decontaminator bracket (cover) off. The HPU reservoir promptly filled with rain water.

The plastic top seems to warp slightly over time leaving a slight gap between the top and bottom on some units.

I used hydraulic jack oil in mine. the units are SPX units just like the jacks on 4 post automotive lifts. we have used that type of oil for years with no issues