brake fluid

I did find this article which has some of the info i had mentioned in a previous post.

SILICONE BASE BRAKE FLUID (SBBF)
The U.S. DOT defines silicone brake fluid as that which consists of no less than 70 percent of adiorgano polysiloxane by weight. Silicone-based fluids are regarded as DOT 5 fluids. They are highly compressible and can give the driver the feeling of a spongy pedal. The higher the brake system temperature, the more the compressibility of the fluid--increasing the feeling of a spongy pedal. Silicone-based fluids are non-hydroscopic, meaning that they will not absorb or mix with water. When water is present in the brake system, it will create a water/fluid/water/fluid situation. Because water boils at approximately 212 degrees F, the ability of the brake system to operate correctly decreases, and the steam created from boiling water adds air to the system. It is important to remember that water may be present in any brake system. Therefore, silicone brake fluid lacks the ability to deal with moisture and will dramatically decrease a brake systems performance. Silicone brake fluid has a number of strengths and drawbacks.

Strengths:
1) It has a high boiling point since it does not absorb water. Therefore, there's no so-called wet boiling point.

2) Doesn't absorb moisture.

3) Doesn't remove paint.

4) The viscosity is more stable over the extremes of temperature.

5) With the exception of some formulations used in external boots, silicone brake fluid is compatible with all standard brake components.

Drawbacks:1) It's hard to pour without entraining air bubbles--hence an application will generally have a softer, spongier pedal feel.

2) It doesn't absorb water, so any water already in the system accu-mulates in the lowest point of the system and stays there, causing rust.

3) Glycol fluids begin to compress near their boiling points, whereas silicone fluids begin to compress at around 300-350 degrees Fahrenheit.

4) Additives in the fluid can vaporize at comparatively moderate temperature, increasing the spongy feel.

5) Silicone fluids expand significantly when hot.

6) Silicone fluid is functionally incompatible with systems that have held glycol-based fluids for any length of time, requiring flushing and seal replacement (there are counter opinions on this, which state that the modern silicone formulations are in fact compatible with only a flushing, rather than a complete reseal). The actual DOT specification requires chemical compatibility, so as far as that goes, the two fluids won't cause reactions if used in the same system, but they certainly won't mix, either.