Brake Fluid

Brake fluid is used in hydraulic brake and clutch applications in the Hyundai Genesis Coupe. It's used to transfer pedal force into pressure which amplifies braking force. Brake fluid works because liquids don't like to be compressed. In their natural state, liquid molecules don't have internal voids so they don't pack together well. Forces are directly transferred from one molecule to another.

All brake fluids must meet standards set by organizations such as the SAE. Brake fluids sold in North America are classified by the USDOT with ratings such as "DOT 3" and "DOT 4". Approved fluids must be colorless or amber to be acceptable for street use in the U.S. except for DOT 5 silicone, which must be purple. (This is why Ate Super Blue was taken off the market and replaced with Ate Typ 200 yellow/amber fluid.)

Boiling point - Brake fluid must have a high boiling point to avoid vaporizing in the lines at high temperatures. Vaporization is a problem because vapor is highly compressible relative to liquid, and negates the hydraulic transfer of braking force - so the brakes will suddenly fail to stop the car. Quality standards refer to a brake fluid's "dry" and "wet" boiling points. Wet boiling point, which is usually much lower (although above most normal service temperatures), refers to the fluid's boiling point after absorbing a certain amount of moisture.

Most professionals agree that glycol-based brake fluid, (DOT 3, DOT 4, DOT 5.1) should be flushed/changed every 1–2 years under non-racing conditions and much more frequently in track or racing use.