What do the terms dry boiling point and wet boiling point of brake fluid mean?
2 Answers
Brake fluid dry boiling point refers to the boiling point when the fluid is freshly added to the brake system from a sealed container; wet boiling point indicates the boiling point after 2 years of use when the fluid contains 3.5% water. Below are precautions for brake fluid usage: 1. Do not mix: Avoid mixing different types or brands of brake fluid. Due to differing formulations, mixing can degrade the fluid's performance indicators. 2. Moisture or contaminant absorption: When brake fluid absorbs water or contains impurities, it should be promptly replaced or filtered, otherwise it may lead to insufficient braking pressure and affect braking performance. 3. Replacement: For vehicles driven normally for 40,000 km or when brake fluid has been in continuous use for over 2 years, the fluid is prone to deterioration due to prolonged use and should be replaced promptly.
I remember when I first started driving, I was most afraid of brake problems. The dry boiling point refers to the boiling point temperature of new brake fluid under high temperatures when it's just been added, which is the state before the fluid absorbs any moisture. The higher the boiling point, the more stable the braking performance, especially during long-distance driving or downhill routes when the brake pads get as hot as fire, making it less likely for steam bubbles to form. The wet boiling point, on the other hand, is the boiling point after the brake fluid has been used for half a year or a year and has absorbed moisture from the air. At this point, the boiling point decreases, and if there's too much moisture, the boiling point drops significantly, potentially causing brake failure. It's terrifying when you feel the pedal becoming soft and the brakes not holding. That's why people often say that according to DOT standards, for example, DOT 4 brake fluid should have a dry boiling point above 200°C and a wet boiling point above 150°C to be considered safe. Every time I go for maintenance, I ask them to test the boiling point, and I never let it go beyond two years without changing the fluid. In short, the boiling point directly affects your life—don't skimp on that little bit of money; changing the fluid gives you much more peace of mind.
