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Vehicle manufacturers recognized the need for a fluid that resisted high temperatures, had lubricating capabilities, had a low freezing point and resisted corrosion. Almost all vehicles on the road today use brake fluid designated DOT 3 or DOT 4. DOT stands for Department of Transportation. The DOT established the standards by which brake fluid, among other things, is regulated.
Some vehicles have been built using a silicone-based (DOT 5) brake fluid, but these are few and far between. DOT 3 and 4 fluids are petroleum-based liquids. Silicone fluids are, of course, not petroleum-based and are completely incompatible with other types and may cause damage to the rubber seals if added to systems that are not designed for silicone fluid. There are 2 chief advantages to silicone-based brake fluid. For one thing, it has a superior ability to withstand heat. And for another, it does not share the petroleum-based fluid's tendency to absorb moisture. However, petroleum based fluids are perfectly able to withstand the heat generated by just about all modern vehicles. If you maintain the DOT 3 or 4 fluid in your brake system through periodic changes, and keep the system sealed to protect it from dirt or moisture, silicone based fluids are unnecessary.
The best rule of thumb with brake fluid is to use the fluid recommended by your owner's manual. Changing the fluid from DOT 3 to DOT 4 is often allowed, but do not change from DOT 3 or 4 to DOT 5.