At 09:55 AM 2/8/99 -0800, Mark Radelow wrote:
>Silicon Fluid can and WILL destroy the seals in my VW. I have seen it
>happen on another car. Futhermore, silicon fluid is much more
>compressable than non-silicon fluid so your pedal feel will be SO much
>shitier. Plus silicon fluid can lead to much worse corrosion in your
>entire system. The reason being ANY water in a silicon system, since it
>is not absorbed, collects in pockets. Then is just sits in that one
>position and corrodes it to hell.
>
>Mark
>
Mark, et Listers,
Those longer term subscribers to the list know this to be a perennially
debated question; the pros and cons of silicon(e) brake fluids. Silicones
do work for some people and have the distinct virtue of not damaging paint.
My impression is that this inertness does extend to other materials such as
seals, etc. In fact, this may be one of its shortcomings, since a little
"activation" of the rubber seals may be needed to help them conform to the
bore surfaces and ensure a good seal. I also suspect silicone based fluids
aren't as lubricating as conventional glycol hydraulic fluids. I will take
Mark's emphatic statement about destroying seals in VWs under
consideration, although with a scientist's typical skepticism for the time
being. I certainly completely agree about the bad effect of silicone
fluid's lack of moisture absorption wrt water corrosion. However, fluids
are, without exception, non-compressible. A soft pedal with silicone fluid,
a problem I've encountered myself, is either the result of trapped air in
the system or, when hot, water converting to steam.
On your recommendation Mark, I'll probably be ordering some of the
Luca-Girling DOT 5.1 soon. Even at $22/L, it's a lot cheaper and easier
than driving to Savannah, Ga.
Bob
Robert L. Palmer
Dept. of AMES, Univ. of Calif., San Diego
rpalmer@ames.ucsd.edu
rpalmer@cts.com
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