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Re: Hydraulic fluid alternatives?
At 08:27 AM 9/29/98 -0700, you wrote:
>As promised, here are the listings from the various hydraulic fluids. I
>typed these up from the side of each bottle. I can't guarantee that
>there aren't any typos; please let me know if you are suspicious of one.
>
>Pentosin 7.1 / Audi G 002 000 (green cap, 1988 and earlier)
>-----------------------------------------
>1. Gas oils (petroleum) straightrun, clay-treated
> CAS: 92062-35-6
Produced directly from petroleum by distillation without other chemical
processes be8ing applied. Clay-treated? Filtered through clay? Other
than removal of possible particulate I'm not sure what this might accomplish.
>2. 2-propenoic acid, 2-methyl-, dodecyl ester, polymer with
>methyl-2-methyl-2-propenoate and tetradecyl 2-methyl-2-propenoate
> CAS: 68171-50-6
A copolymer with two listed components. This is most likely a synthetic
produced in a chemical plant. Viscosity modifier?
>3. White mineral oil (petroleum)
> CAS: 8042-47-5
I forget the temperature range but distillation fractions from petroleum
are identified as gasoline, mineral oil, No. 2 home heating oil (diesel
fuel), etc., by different boiling point. This is simply another component
from petroleum. Probably a higher boiling point than #1 above.
>4. Distillates (petroleum) solventrefined [sic?] heavy paraffinic
> CAS: 64741-88-4
Paraffin is a solid (at room temperature) mixture of alkanes. It is also
produced by distillation of petroleum.
>5. Phosphorodithioc, o, o-di-Cl-14-alkyl esters, zinc salts
> CAS: 68649-42-3
Synthetic. Purpose? Bactericide? My guess.
>Ford Hydraulic Brake Oil M6C34A
>-------------------------------
>1. Distillates (petroleum), solvent dewaxed heavy paraffinic
> 64742-65-0
A mixture of components - not specified. This *may* be essentially the
same as a combination of 1,3, and 4 above. Then again...
>2. Phenol, dimethyl-, phosphate (3:1)
> 25155-23-1
Probably another bactericide. My guess.
This product may be quite suitable as a replacement for pentosin 7.1. If
you try it, I'd suggest a complete system flush so that the dimethylphenol
phosphate will not be in the system with component 5 above.
>And, while I'm at it:
>
>Pentosin 11s / Audi G 002 000 (red cap, since 1989)
>---------------------------------------------------
>1. 1-Decene, dimer, hydrogenated
> CAS: 68649-11-6
>2. Distillates (petroleum) solvent - dewaxed light paraffinic
> CAS: 64742-56-9
>3. 2-propeonic acid, 2-methdodecyl-ester, polymer with
>methyl-2-propenoate and tetradecyl ethyl-2-propenoate
> CAS: 68171-50-6
>4. White mineral oil (petroleum)
> CAS: 8042-47-5
All of the 3 above are more or less the same as pentosin 7.1.
>5. Amines, polyethylene polycompounds with (polybutenyl) succinic
>anhydride
> CAS: 68439-90-5
Interesting. Another polymeric material which might have rather
significant effect on the viscosity of the product. It might also have the
capability of reacting with and thereby removing any acidic materials in
the system. Where might these come from? I have no idea.
My own reaction would be to stick with the pentosin product specified for
your car. The pentosin 11s should substitute for pentosin 7.1 quite well.
The Ford product _may_ be OK also. Then again... I'd rather pay the extra
price and be _sure_ it's OK.
>That's it. Any interpretations of the similarities and differences? My
>first observation is that the Ford fluid doesn't have much in it,
>compared to the others. I'm also surprised that mineral oil is not on
>M6C34A's list; I've seen many references to 7.1 as "mineral oil."
Mineral oil is simply one of the mixtures of petroleum distillate
materials. It's probably there, grouped with other distillation fractions
and called, collectively, petroleum distillates.
>(The
>Ford fluid has been suggested as an alternative to 7.1, not 11s, by the
>way.)
This may be an appropriate substitution. I suspect that 11s boils at a
higher temperature than 7.1. Kinda like DOT4 brake fluid is suitable for
use in a car which is signed as using DOT3. DOT3, however, is probably not
a good substitute for DOT4.
Pentosin 11s will probably substitute quite well for 7.1. I'm not sure if
I'd be willing to substitute the other way.
Hydraulics 101: (as viewed by a definite nonprofessional)
We need an incompressible but fluid substance to work as a hydraulic fluid.
Just about any true liquid would sere here. Certainly any of the three
would suffice for this quality.
We need a material which will not freeze at lower temperatures. To do this
requires either a single low melting component or a mixture of components,
each depressing the melting points of the others. We have a such mixture
in each case.
We need a material which will not boil away under severe temperature
conditions. Boiling points will probably be rather different from one
product to the next. Which will be the highest? Lowest? Dunno. It
depends on several factors about which I have no information.
We need a substance which will not corrode the metal of the pump, etc.
None of the three should do this. All could be substituted for a fine oil
in a pinch. No, I'm not suggesting that you should add pentosin to your
engine in place of oil. Not even in an emergency.
We need a substance which will not degrade the various rubber components of
the system. These interactions are rather difficult to predict. I see
nothing in any of the three which suggests an incompatibility with rubber.
Unfortunately, the best (only?) way to determine this is to do the test.
Sorry. I wish I could give a definite recommendation. I can't.
___
Bob
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