What Is Brake Fluid?
What Does Brake Fluid Do?
Estimated reading time 3:45
What is brake fluid and what does brake fluid do? Brake fluid is one of a braking system’s most overlooked performance parts. Whether you’re driving to work or enjoying a day on the track, the most important mechanical system in your car or powersport vehicle is arguably your brakes.
The chief purpose of brake fluid is to convert brake pedal pressure into stopping power while remaining stable in various conditions. To illustrate, when the brake calipers (and the fluid reaching them) get hot, the fluid will often boil.
The boiling process produces gas, which is more compressible than the fluid. Consequently, it leaves you with a soft, spongy brake pedal feel and a longer travel time when applying the brakes. It can be a very unsettling feeling, not to mention unsafe.
Additionally, brake fluid is hygroscopic. In other words, it absorbs moisture from the atmosphere, which takes place over time. When the fluid contains water, it starts to boil with less heat.
Because brake rotors and calipers generate excessive heat, the brake fluid must have a high heat tolerance. Otherwise, the fluid would vaporize inside your brake lines and create a dangerous situation because your brake system will not function properly.