IML: Dot 5 conflictions

Since brakes are always a concern, and enter into conversation, I thought it prudent to make some remarks. Some things I've learned, I will share with the group. The development of different grades of brake fluids,came about because of changes / improvements in the braking systems themselves. Everyone has heard the term: "Brake Fade"With drum type it is common, the cause, may be unknown to most, and there is little to cure it. During several high speed stops, the drum is heated to very high temps, and increases in diameter, it also becomes flexible. The brake shoes, on the other hand expand at a different rate (less). This results in less braking contact surface, thus less stopping power. You'll note that later model brake drums have cooling fins, and a bit more material around the edges. Disc brakes however, maintain constant braking surface, and stop more consistently, even with a lot of heat in the system. The changes in fluids came about, because the disc brake system subjects the braking heat more directly to the fluid. The brake pad is in direct contact with the caliper piston, thus transferring much more heat to the fluid, causing it to boil creating vapor bubbles, and fade. Drum brakes transfer much less actual braking heat to the fluid, and the brake backing plate acts as a heat-sink for the wheel cylinders. One point I would make, if you experience a hard panic stop, or are towing and know you've put high heat loads in the brake system, once stopped shift to neutral / park release the brakes, and allow the drums/discs to cool uniformly. Keeping the brakes applied will cause uneven heat dissipation, and possible warping of drums, or rotors. Changing fluid to remove contaminants, and moisture is surely good practice (remember water boils @212 creating fade). Dot 3-4-5 your choice, but remember there's no such thing as a "Cure in a Can", for design limitations. Ya'll have a nice day, Dave.