In a message dated 2/16/01 12:05:31 PM Eastern Standard Time,
james.f.juhas@snet.net writes:
> Can you review the current thinking on the issue of using silicone fluids?
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I did a lot of research a few years ago, using the tech pages at www.vtr.org,
and lots of great help on this list. I decided on Castrol GT LMA, which is
DOT 4. The case against silicone is pretty weak, but I could find no fault
at all with DOT 4 other than it removes paint, and switched both of my cars
over.
Silicone fluid will not absorb water, which means that any water that gets
into the system (from humidity in the air) will form droplets, and if left
for a long enough period, it will pool at the low points in the system. If
you use the car frequently, this will be less of a problem, but if the car
sits for months between use, it "could" cause rust in the lines or cylinders.
The cure is to change silicone fluid annually. Since you should be changing
brake fluid regularly anyway, this is probably not too important.
Silicone causes seals to swell (or not to swell, I don't know which) at a
different rate than DOT 4 fluid, so if you change from one type to the other,
it is best to completely rebuild the system and replace all the rubber bits,
and flush all the old fluid out thoroughly.
Glad I got all that off my chest. It's been a while since the last "silicone
fluid" thread.
Allen Hefner
SCCA Philly Region Rally Steward
'77 Midget
'92 Mitsubishi Expo LRV Sport
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