What Kind of Oil Is Brake Fluid?
3 Answers
Brake fluid, also known as hydraulic brake fluid, is the liquid that transmits force in a vehicle's braking system. Like engine oil, brake fluid is a synthetic oil blended with various additives and has strong hygroscopic properties. Brake fluid is also classified into different grades. According to the American Petroleum Institute (API) standards, brake fluid is categorized into three grades: DOT3, DOT4, and DOT5.1. Below are the specific consequences of not replacing brake fluid for an extended period: Corrosion of the braking system: Brake fluid is inherently hygroscopic and readily absorbs moisture. If not replaced for a long time, it can corrode the braking system, posing significant safety risks. Formation of vapor lock: When brake fluid absorbs water, its boiling point decreases, which can lead to insufficient braking pressure and compromised braking performance. When the temperature rises to the boiling point, the absorbed water in the brake fluid vaporizes, creating air bubbles. Clogging of the brake system: Prolonged failure to replace brake fluid allows deposits and impurities to accumulate in the brake lines, potentially causing brake system malfunctions and degraded braking performance.
Brake fluid isn't the kind of oil we usually talk about. It's a special liquid used in a car's braking system, responsible for transmitting the force from pressing the brake pedal to the brake discs on the wheels. After driving for a few years, I've come to understand its hygroscopic nature: it absorbs moisture from the air, and when it contains too much water, high temperatures during braking can cause it to boil and create air bubbles, leading to brake failure! That's extremely dangerous. It must be replaced every two years or according to the mileage specified in the manual. There are types like DOT3 and DOT4, with DOT4 having a higher boiling point and being better. Last time I didn't change it on time, my brakes became spongy and I almost rear-ended someone. Now, I always remind myself to check it—safety first. Remember, it's highly corrosive, so avoid contact with your skin. Every driver knows that neglecting brake fluid is like gambling with your life.
I'm a new driver who just started learning. My instructor told me that brake fluid isn't actually oil, but a hydraulic medium. When you press the brake pedal, it transmits force through the pipes to each wheel component, ensuring the car stops. Interestingly, it's highly hygroscopic and absorbs water. When too much moisture accumulates, its boiling point drops, which can cause steam bubbles to form in the brake system, leading to failure. It must be replaced regularly—every two years or 20,000 kilometers. I chose DOT4 type for my car, which has a higher boiling point and is slightly better than DOT3. This was repeatedly emphasized in my safe driving course, so I check it during every maintenance service. The risks of not replacing it are significant, especially during rainy days or mountain driving, where accidents are more likely. Changing the fluid is simple and can also extend the lifespan of your brakes.
