What is the Function of Brake Fluid?
2 Answers
The functions of brake fluid are as follows: 1. The characteristic of brake fluid is to ensure flexible transmission of braking force under working conditions such as high temperature, extreme cold, high speed, and humidity. 2. It is non-corrosive to both metal and non-metal materials in the braking system. 3. It effectively lubricates the moving parts of the braking system, extending the service life of brake wheel cylinders and rubber cups. Precautions for purchasing brake fluid: 1. Check the product's viscosity and color. Brake fluid that is too thin cannot be used, and colorless or transparent fluid is also unacceptable (qualified brake fluid is generally light yellow or dark yellow). Qualified brake fluid is noticeably thicker than water, resembling diluted honey, and spreads slowly when poured on a glass plate. 2. Inferior brake fluid has a viscosity as thin as water, spreads quickly when poured on a glass plate, and feels lacking in thickness when dipped with a finger.
After driving for so many years, I've found that brake fluid plays a central role in the braking system. It acts like a messenger for braking force—when I press the brake pedal, the fluid quickly transmits the pressure from my foot to the brake calipers, causing the brake pads to clamp onto the discs and slow down or stop the car. More importantly, it can withstand high temperatures to prevent vaporization and bubble formation, which would otherwise make the brakes feel spongy. I still remember an emergency stop on the highway when the old brake fluid, degraded over time, had a lower boiling point and nearly failed. Since then, I’ve made it a habit to replace it every two years, opting for DOT 4 type for better reliability. During maintenance, I always check its color and level—if it’s discolored or contaminated with moisture, it needs replacement to avoid corroding the lines or causing pump leaks.
