What is the Function of Brake Fluid?
3 Answers
Brake fluid functions to transmit energy, dissipate heat, prevent corrosion and rust, as well as provide lubrication. The method to determine when brake fluid needs replacement is: when the water content in the brake fluid reaches 3%, it must be replaced immediately. The steps to replace brake fluid are: 1. Park the vehicle on level ground and turn off the engine, then open the hood and drain the remaining brake fluid; 2. Use a funnel to fill the reservoir with new brake fluid; 3. Press the brake pedal inside the car until the fluid level in the reservoir under the hood reaches the lower limit. Precautions for using brake fluid: 1. Avoid mixing with gasoline or engine oil; 2. Replace it regularly; 3. Choose high-quality brake fluid.
I've run an auto repair shop for ten years, and brake fluid is the lifeblood of the braking system. It converts the force from your foot on the brake pedal into hydraulic pressure to push the calipers, allowing the brake pads to clamp the rotors. If the fluid is low, deteriorated, or contaminated with moisture, the brake pedal will feel spongy or even fail, especially noticeable in rainy weather. Last time, a car owner hadn't changed the fluid for three years, with moisture content exceeding 3%. The actual braking distance was 7-8 meters longer than when the car was new—extremely dangerous. I recommend changing it every two years or 40,000 kilometers, and always go for DOT4 standard.
As a female car owner, I only realized the importance of maintenance after experiencing brake fluid depletion. This blue liquid isn't just a force-transmitting medium—it also withstands 350°C high temperatures to prevent boiling. Last summer while descending a mountain road, my brakes started shuddering. Inspection revealed the old brake fluid was full of air bubbles, creating vapor lock from the heat that nearly caused an accident. Now I've developed habits: monthly checks of the reservoir's level marks under the hood, and mandatory moisture content testing during biennial fluid changes. Humid southern regions require more frequent changes—after all, brake failure is far more serious than a botched manicure.
