Your Brake Fluid FAQs Answered

Choosing which brake fluid to use and knowing how often it needs replacing can be tricky. To help, we’ve put together this essential FAQs guide covering what Prestone DOT 4 Brake Fluid is and how often you’ll need to use it.

What is DOT 4 Brake Fluid?

DOT 4 brake fluid is a premium quality brake fluid with a high boiling point. At Prestone all our brake fluids have a DOT 4 rating, as we believe this offers the best performance, safety, and protection for your car’s brake system.

DOT stands for Department of Transport, with the numbers being a rating from 1-5 showing the characteristics of a particular type of brake fluid. Generally the higher the number, the better the performance and protection (though you should always refer to your car’s manual when choosing brake fluid).

If you’d like to learn more about what DOT 4 brake fluid is and how it compares to other products, click here to read our comprehensive guide to understanding brake fluid.

How do I replace Prestone DOT 4 Brake Fluid?

If you’re confident at fixing and maintaining your car, replacing the brake fluid is definitely something you can do at home. Otherwise we’d recommend leaving this job for the professionals.

Fancy replacing brake fluid yourself? Follow the steps below.

What you’ll need

  • Turkey baster
  • Lint-free cloth
  • Small container (to catch the old brake fluid)
  • Rubber gloves


  1. Locate the brake fluid reservoir and use a turkey baster to remove as much of the old fluid as you can, depositing it in your empty container.
  2. Fill the system with Prestone DOT 4 Brake Fluid to the ‘max’ fill line. Do this quickly – the less time brake fluid makes contact with air, the better.
  3. Next you’ll need to bleed the brakes to force the remaining old fluid out of the system. If you don’t know how to do this, our guide can help.
  4. When you’ve bled the brakes, recheck the brake fluid level and top up if necessary.

And that’s it, you’ve successfully replaced your car’s brake fluid. Be sure to drive slowly around the block if it is safe to do so, to check that your brakes are working OK.

How often do I need to use Prestone DOT 4 Brake Fluid?

Brake fluid doesn’t need changing very often. A professional mechanic will check the level and condition with each annual service, and advise if and when it needs replacing. Generally you can expect to replace the brake fluid every 1-2 years, but this depends on your mileage, driving style, and the make and model of your car.

There are of course a few signs that can tell you when it’s time to change your car’s brake fluid. These include:

  • Strange noises when braking
  • A burning smell when the brakes are applied
  • The ABS warning light

If you notice any of these signs, be sure to check and change your car’s brake fluid as soon as possible, or else take your car into a garage to have it checked over by a professional.

For more information on Prestone DOT 4 Brake Fluid, or any of the other products in our high-performance car maintenance range, click here.