What does DOT mean for brake fluid?
2 Answers
DOT is the minimum boiling point standard data, a specification grade stipulated by U.S. automotive safety standards. Here is additional information: 1. Definition of brake fluid: Automotive brake fluid, also known as hydraulic brake fluid, is the liquid used to transmit pressure in automotive hydraulic braking systems. It is a crucial product related to traffic safety. Brake fluid is made from refined diesel distillates with thickeners and antioxidants added. There are three types: mineral oil brake fluid, alcohol-based brake fluid, and synthetic brake fluid. 2. Braking working pressure of brake fluid: The braking working pressure of brake fluid is generally 2MPa. All liquids have the characteristic of being incompressible. In a sealed container or a pipeline filled with liquid, when the liquid is subjected to pressure, it quickly and uniformly transmits the pressure to all parts of the liquid. Hydraulic braking works based on this principle. After being used for a certain period, brake fluid tends to have a lowered boiling point, become contaminated, and undergo varying degrees of oxidation and deterioration.
I've been driving for over ten years. DOT actually stands for the Department of Transportation in the US, which specifically sets performance standards for brake fluid. These standards aren't arbitrary—there are several grades. For example, DOT 3 is suitable for regular passenger cars with a lower boiling point of around 205°C; DOT 4 has a higher boiling point, exceeding 230°C, making it ideal for long-distance or mountainous driving; DOT 5.1 has the highest boiling point, over 260°C, and is designed for racing cars. Brake fluid absorbs moisture and degrades over time, causing its boiling point to drop. This can lead to fluid boiling during downhill driving, resulting in brake failure. I remember my last brake fluid change was two years ago—replacing it every two years is crucial. Always check your vehicle's manual for the recommended type. Never mix different DOT grades, as it can damage the braking system. Safety comes first!