Brake fluid DOT primer

So you go to top off the brake fluid, and it says "DOT 3" or "DOT 4" or "DOT 5". What's that mean?

Brake fluid is engineered to do specific things in specific ways. So it's important to put the right kind in your car or truck.

DOT 3 and DOT 4 brake fluids are glycol-based. They're used in most modern cars and trucks, because they work with ABS brakes. DOT 4 has a higher boiling point than DOT 3. You can use DOT 4 where DOT 3 is called for, but not the reverse. Using DOT 3 in a DOT 4 brake risks boiling the brake fluid. Glycol-based fluid can absorb water over time, which leads to corrosion. It also changes the quality of the fluid in braking. This is one reason to have your brake fluid changed regularly.

DOT 5 is silicone-based. Its advantage is that it doesn't absorb water, so it doesn't corrode brake systems. However, it doesn't work with ABS brakes. So it's mostly for older cars and trucks.

Have a question about your brakes and brake fluid? Feel free to stop by any of our stores and have them checked out.

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