What is Motor Vehicle Brake Fluid?
3 Answers
Here is the relevant introduction about automotive brake fluid: 1. Automotive brake fluid is a liquid medium that transmits braking pressure in hydraulic braking systems, used in vehicles equipped with hydraulic braking systems. 2. Brake fluid, also known as brake oil or force fluid, is an indispensable part of the braking system. In the braking system, it serves as a force transmission medium. Since liquids cannot be compressed, the pressure output from the master cylinder is directly transmitted to the wheel cylinders through the brake fluid. 3. Because the seals in the braking system are made of rubber, prolonged immersion in brake fluid can cause chemical changes, leading to expansion or contraction of the rubber seals, thereby affecting braking performance. Therefore, it is essential to choose brake fluid that is highly compatible with rubber.
I'm just an ordinary car owner who drives, and I knew nothing about brake fluid until one time when the brakes felt sluggish. The mechanic checked and said it was a brake fluid issue. It turns out brake fluid is the specialized liquid used in a car's braking system—it transmits pressure to make the brake pads clamp the wheels, stopping the car. It's glycol-based and comes in grades like DOT3 and DOT4, with the key ability to resist high temperatures and corrosion. During daily driving, moisture gradually seeps into the fluid, diluting it. If it boils, pressure is lost, and brake failure could lead to an accident. So now, I replace it every two years or 40,000 kilometers to ensure driving safety. Remember, have a professional shop regularly check the fluid level and color changes. If it appears cloudy or drops too quickly, address it immediately—don't skimp on the cost, as it concerns your safety.
With years of driving experience, I can say that brake fluid may seem simple, but it plays a core role in the braking system. It serves as a hydraulic medium, transmitting the force from the brake pedal through the master cylinder to the wheel cylinders and calipers, enabling the vehicle to slow down and stop. Different vehicle models require different specifications—for example, the commonly used DOT4 has a higher boiling point, making it suitable for high-temperature environments, while DOT5 silicone-based fluid is better for long downhill stretches as it resists bubbling. Though it may seem insignificant, excessive moisture absorption can lower the wet boiling point, leading to insufficient pressure and outright brake failure. It's advisable to replace it according to the manual's recommended intervals. Before driving, quickly check the reservoir's indicator line—clear and transparent is ideal. If the brakes feel spongy, don’t delay—get them inspected immediately.
