Brake Fluid

[Ameer Antar]

>Don't know about DOT 1 or 2 (can't recall seeing them), but DOT 3 and 4 are

agreed, DOT1,2 are not available...they're just a general temp rating for fluid

>DOT 5 is silicone.  I don't believe there is a DOT 5 synthetic.

DOT5 IS synthetic b/c "Silicones are synthetic polymers and are not 
therefore found naturally"

>DOT 5 is a higher performance fluid than 3 & 4 but I believe frequent
>changes are recommended (I think because it IS hydroscopic, but I'm not
>sure).

At http://www.baer.com/faq.htm they say this about DOT5:

"Silicone-based fluids are great for museum cars that are never driven 
because the fluid is very non-reactive. You can spill some on the car's 
paint without fear of damage. While this is good for museum cars, it's bad 
for a car that's ever actually driven.
Although water is always going to get into the brake lines and hoses, it 
will not dissolve in the silicone fluid. This water forms pockets that will 
boil off and become steam as the brake fluid heats up with use. As a 
result, it is virtually impossible to keep a silicone-based system bled 
properly, as there will always be gas in the lines."


>Whether or not using a blend is a sin, I don't know (I never have and sort
>of don't see the point), but (not to flame anyone here) I'd like to know
>what was so "unimpressive" with them.

I personally didn't like Castrol syntec blend b/c it was thin and slipped 
through gaskets on a Chevy motor. Also it burned very quickly, leaving 
varnish and crud, and making the oil very black. Plus it doesn't have as a 
high a rated temp as Mobil1. Porsche's at my Audi dealer use only Mobil1. 
If that's good enough for a Porsche, it's good enough for my turbo 
Audi...I'm sure there are others that are good, like Amsoil, etc., but I've 
had good experience Mobil1, and I like being able to buy oil locally and 
getting it cheaper too...

-ameer