Originally Posted by
S Lathrop
One caution that applies to any brake fluid you use: Once you open a can of fuild, use it or throw it away. Do not use fluid that has sat around the shop for more that a day or 2 after it has been opened.
Water is soluble in brake fluid and for each 1% of water absorbed by brake fluid, the boiling point drops 10 degrees. Brake fluid can adsorbed up to 15%,water depending on the type you have. That means that old fluid in you system can boil at 150 degrees lower that advertised on the can.
When I was running cars, I would change the fluid in the system every couple races and sometimes prior to every race where the tracks required heavy braking.
Now the new brake fluids available today are likely better than what was available 20 or more years ago. But the improvement may only be in the degree to which the newer fluid will become contaminated with water.