A little information about brake fluid

[ITSME4G63]

Tkaen from another forum which took it from a british based one:

Because DOT 3 & DOT 4 fluid is glycol based, it absorbs moisture over time. Moisture seeps in through microscopic pores in the rubbers, seals and hoses, and enters every time someone opens the master cylinder reservoir. Brake fluid is so hygroscopic (water absorbent) that leaving the lid off fresh brake fluid can ruin it overnight. This moisture contamination causes a drop in the fluid's boiling point which can contribute to feelings of brake fade during hard use. When a car's brake fluid is one year old, it contains 2.5% water. By 18 months, the water content can have moved up to 3% which is enough to lower the boiling point of the fluid by 25%. After a few years, the fluid can contain as much as 7% to 8% water.


hope that helps

 

[Morphius]

Actually, within a year, brake fluid is considered saturated. The boiling pt of fresh fluid is 495F and saturated fluid is 275F.

 

[Jehu]

The wet boiling point also depends on the type of brake fluid...For example, the Castrol SRF has a wet boiling point of 518 deg. F, which is more than the dry boiling point of some brake fluids!

But yes, the minimum wet boiling pt required for Dot 3 fluid is 284F.