Question: is brake fluid all the same?
Answer: The three main types of brake fluid now available are DOT3, DOT4 and DOT5. DOT3 and DOT4 are glycol-based fluids, and DOT5 is silicon-based. The main difference is that DOT3 and DOT4 absorb water, while DOT5 doesn't. One of the important characteristics of brake fluid is its boiling point.