Bill,

   Did you mean "DOT 5" fluid?  

   DOT 4 is borate-ester/glycol based, and is compatible
with (but a higher flashpoint than) DOT 3 automotive brake
fluid.

   DOT 5.0 is silicon based; and DOT 5.1 is borate-ester/
glycol again, but more borate and less glycol for *boiling
point* similar to DOT 5.0.

   BTW, although DOT 5.0 won't harm paint, it will render any surface it touchs *unpaintable*.

Regards,
Dale


> From: WRJJRS@aol.com
> Date: 2005/08/25 Thu AM 01:21:58 EDT
> To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> Subject: [FlyRotary] Re: Flamible brake fluid
>
> [quote snipped]
>
> Ed,
> I have checked with several manufacturers who say their stuff is compatible  
> with automotive fluids. I have no idea why we would put up with the flammable  
> aircraft stuff. Besides DOT 4 silicone fluid which has the advantage of not  
> harming paint, I have been using various synthetics in my race bikes for years
>  which are good to better than 600°F! I have heard some older auto fluids are
>  corrosive to aluminum but with the number of aluminum components on modern
> cars  it MUST be less common. I have had all sorts of ALUMINUM BRAKE PARTS
> including  master cylinders on my bikes and never seen ANY problem. The aircraft
> fluid is  simply stupid when compared to modern auto fluids.
>
>