Bob Palmer wrote:
>
> 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
If you have installed the CAT braided metal lines, there's no soft pedal
problem. Conventional fluid eats up the pot-metal bores in the brake
booster. that's a fact. Silicone requires really good flair joints. it
wants to leak out.
Al J.
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