Brake Fluid Available here. Brake fluid is a form of hydraulic fluid that plays an integral role in ensuring optimal operation of a vehicle’s braking system. When a driver pushes down on the brake pedal, this fluid works to amplify braking force by transferring the force into pressure. If a vehicle is low on this fluid it can cause a number of symptoms, such as being able to push the brake pedal completely to the vehicle floor without stopping the vehicle. This can be very dangerous, so it is important to inspect for leaks and to look at the brake fluid reservoir frequently. Refilling this fluid only take a matter of minutes, making it a quick and simple maintenance tasks.