What does DOT4 mean?
1 Answers
DOT4 is a specification grade for automotive brake fluid. Here are the relevant details: 1. Replacement interval: Since brake fluid is alcohol-based, it has strong hygroscopic properties. Over time, its water content gradually increases. After about 12 months of use, DOT3 and DOT4 brake fluids typically contain an average of 3% water content. When brake fluid contains excessive moisture, it can cause delayed braking response and extended stopping distances. Therefore, it is recommended to replace the brake fluid every 2 years (or 40,000 kilometers). 2. Mixing compatibility: Qualified brake fluids of the same quality grade can be mixed. For example, DOT4 brake fluids from major brands can be mixed. However, if the vehicle originally uses low-quality DOT3 brake fluid and is being upgraded to high-quality DOT4, the original brake fluid must be completely drained first.