Brake fluid

[Excaliber]

This quoted from the Wilwood web site:
"Wilwood does not recommend using DOT 5 fluid in any racing applications. DOT 5 fluid is not hygroscopic, so as moisture enters the system, it is not absorbed by the fluid, and results in beads of moisture moving through the brake line, collecting in the calipers. It is not uncommon to have caliper temperatures exceed 200° F, and at 212° F, this collected moisture will boil causing vapor lock and system failure. Additionally, DOT 5 fluid is highly compressible due to aeration and foaming under normal braking conditions, providing a spongy brake feel. DOT 5 fluid is best suited for show car applications where its anti-corrosion and paint friendly characteristics are important."

From Club Cobra:
Silicone brake fluid is very popular with vintage Corvette owners because it does not harm paint and does not absorb water, which could damage valuable original equipment brake system parts. It is also useful for cars in collections which are not driven. It is not recommended for much else.

From Club Cranky racing:
Question was, what do YOU guys use for brake fluid?
Castrol brake fluid like the pro's use costs $75.00 a qt.
Most of us part time wannabe racers use Wilwood Hitemp brake fluid or SS Brakes Hitemp fluid. Their are others not as expensive as the Castrol at around $7.00 a pt.


From the internet:
Boiling point of various brake fluids:
BRAND - wet boil - dry boil - dot

Castrol LMA.....311/446 dot 4
PFC z-rated.....284/550 dot 3
Wilwood 570...284/570 dot 3
AP-551............284/540 dot 3
AP-600............284/572 dot 3
and the liquid gold of brake fluid...
Castrol SRF.....518/590 dot 4

From the "TheBrakeman.Com" web site:
Brake Man577 Our fluid has been specially designed to meet the extreme conditions found in professional competition. With a dry boiling point of 577 degrees, and a wet boiling point of 300 degrees, it beats the competition cold, but does it for a third of the cost of the others. In order to buy a better fluid, you will spend over $25.00 a quart. Remember, what you purchase should match the job. Our brake fluid does just that by offering high temperature resistance, with the quality necessary to make sure that it lasts a long time! It is packaged in 12 oz bottles to keep it fresh and is economical so that you can "freshen the brake system as we recommend, before every race, for best results."
From the book "Engineer to Win", page 189:
"...the silicone brake fluids have made progress since "PREPARE TO WIN" (the book). Some of them are now almost useable in racing cars - but not quite. They still have high frequency vibration frothing problems and they are still compressible at high temperatures, which it is why it takes a few laps for the pedal to get spongy when gullible people try to use silicones to race with. We replace all our brake fluid long before it has a chance to collect moisture so I have never understood why anyone would spend money for the silicone ones anyway."

One more IMPORTANT point.
DOT5 will mix with DOT4 and cause the seals to swell up in caliper pistons, master cylinder and related "rubber" parts of your brake system.