Brake Fluid Brake fluid, also known as hydraulic fluid, is responsible for moving the various components of your vehicle’s braking system. The fluid operates under high temperatures and high pressure and, without it, your car or truck would not be able to stop when you push the brake pedal inside your vehicle. Brake fluid is a non-compressible substance that lies within the brake lines, delivering the force created by your push on the brake pedal to each of the brake rotors on the four corners of your vehicle. This applies pressure to the wheels and ultimately slows or stops your movement. Here is a step-by-step and somewhat simplified look at how brake fluid works within a hydraulic brake system: Enquiry Now The driver depresses the brake pedal. The pedal compresses a piston inside the brake caliper. This compression increases the pressure inside the brake lines and sends the brake fluid into motion. The pressure of the brake fluid then causes the brake rotors to squeeze down on brake pads, which then make contact with the wheels, slowing and eventually stopping wheel rotation and also the vehicle itself. The two main types of brake fluid now available are DOT3, DOT4.