In a message dated 96-10-11 22:55:24 EDT, you write:
<< Some recommend silicon fluid, but be very careful when making your
decision to use this fluid. The advantage of silicon is that it does not
absorb water like regular brake fluid, so supposedly you wouldn't have to
bleed brakes as often (how often do you do it anyway?). It also doesn't
hurt the NATURAL rubber brake parts found in all MG brake systems. The
disadvantage is that it makes an already soft brake pedal even softer. The
other disadvantage is that when deciding to convert, you must FULLY flush
the entire system to change it. When silicon and regular brake fluid
combine, a solid precipitate falls out of solution-- meaning bad stuff.
So even a trace of the regular brake fluid could cause problems with the
brakes.
>>
Well, here we go again on this old thread. These days when it comes up I
mostly delete the message unless some real misinformation is being spread. I
have 8 years of experience using DOT5 in 4 MGs and one Triumph. Some of my
friends have been using it for over 14 years in their MGs. It is true that
if one is going to use it, the the brake system should be totally rebuilt (
agood idea anyway) and the lines flushed (to get rid of the moisture laden
DOT3 or 4). It is absolutely not true that combining the two fluid causes a
precipitate to fall out. The two fluids can in fact be used together but no
one recommends this. Also I defy anyone to tell the difference in pedal
pressure between the two different fluids. If you have a soft pedal you have
air in your system. Period. Lately silicone fluids have been taking a hit
because they do not absorb water like DOT 3 & 4, so the theory goes that the
water lays in the low parts of the system and corrodes stuff there. In my
limited experience, I have never seen this. I have however seen lots of
corrosion from water in DOT 3 and 4. Where is the water in DOT 5 coming
from??
My understanding is that DOT 3 is an outdated fluid and that if one opts for
a glycol based fluid you should use DOT4 and it must be completely flushed
every two years or so. If you use your car as a daily driver, this time span
can be lengthened because the heat of the the braking system tends to dirve
off the moisture.
The best article on Silicone brake fluid is still the one that appeared in
Skinned Knucles a few years ago.
My cars sit for long periods of time between driving, I never have brake
fluid problems anymore. I use DOT5. Like most things in life, it a
tradeoff......make your decision and live with the results...........
Cheers
Terry
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