How many kilometers should brake fluid be replaced for a sedan?
2 Answers
Brake fluid should be replaced every 40,000 kilometers or 2 years for a car. The functions of automotive brake fluid are as follows: 1. The freezing point of automotive brake fluid is very low, ensuring good fluidity at low temperatures. 2. The boiling point of automotive brake fluid is extremely high, preventing vapor lock at high temperatures. 3. The quality of automotive brake fluid changes very little, avoiding corrosion of metals and rubber. 4. Brake fluid is composed of refined diesel distillates combined with thickeners and antioxidants, and there are three types: mineral oil brake fluid, alcohol-based brake fluid, and synthetic brake fluid. The requirements for brake fluid include good viscosity-temperature performance, the ability to work over a wide and low temperature range, and excellent oxidation stability, anti-foaming properties, resistance to rubber swelling, and rust prevention.
Over the years of driving, I've learned that the brake fluid replacement interval is particularly crucial—don’t wait until the brakes feel spongy to act. Generally, it’s recommended to change it every 20,000 to 30,000 miles because brake fluid absorbs moisture over time, lowering its boiling point. During hard braking, high fluid temperatures can lead to vapor lock, causing brake failure. This is no trivial matter, especially on mountain roads or highways, where a single mistake could lead to disaster. I usually refer to the vehicle manual or consult a professional technician for guidance. If you frequently drive in humid conditions, like during southern rainy seasons, or face stop-and-go traffic with constant braking, consider replacing it earlier. Regularly checking the fluid’s color and moisture content helps prevent issues. Safety comes first—don’t cut corners on small expenses that could compromise your entire vehicle’s safety.
