The more I research, the more brake fires I come across occurring in experimental aircraft.  However, it turns out the standard brake fluid is widely used throughout general aviation as well as airlines - this is the standard 5606 series.  The flash point has ranged from 187F to 240F as some improvements in flash point was made with each new formula up through Mil-P-5606H.

 

Attached in PDF format is a concise article from EAA chapter 493 about an RV-8 brake fire and the crucial difference between the old standard and the new brake fluid Mil-H-83282.  The new brake fluid is compatible in every way with the standard - but has a flash point around 400F - almost twice that of our standard brake fluid.  It turns out the standard brake fluid has been responsible for airliner crashes, GA crashes as well as numerous fires. 

 

Your brakes are hot enough even with moderate braking to immediate ignite the standard brake fluid - if you have any kind of leak and the fluid contacts the brake pads or rotor - its quite possible you will find your aircraft on fire as I did.

 

Naturally I strongly recommend a change to the H-83282 as soon as practical - like no later than your next annual/conditional inspection if not sooner.  Me I'm doing it sooner.

 

Ed

 

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.