Brake Fluid. Do you need to replace it?


Why is it important to replace my brake fluid?  Most brake lines are made of something called Bundy tube or Bundy pipe, which are steel pipes lined with copper.  The copper corrodes over time, which can damage your brake system.  Copper corrodes when dissolved oxygen and acid reacts with the metal.  Brake fluid is acidic and there is no way to completely avoid the presence of oxygen in the fluid, therefore corrosion is inevitable.  Inhibitors in the brake fluid help prevent this corrosion, but the inhibitors eventually break down because of the high level of heat in the brake lines.  Therefore, it is necessary to replace the brake fluid so that the level of inhibitors is high enough to prevent copper corrosion.

How does copper corrosion damage my brake system?  The answer to this question is a bit scientific.  Copper corrosion results in copper ions in your brake fluid.  The copper atom loses one of its electrons, thus turning it into a free-roaming ion.  The copper ion searches for another electron to replace the one it lost, and finds this electron in the iron brake parts.  When the iron atom loses an electron to the copper ion, it corrodes just like the copper did, and the copper plates itself to the iron brake parts.  This is what destroys the brake system.  To make matters worse, the electron that is lost from the copper atom forms oxygen in the brake fluid, and this oxygen accelerates copper corrosion, making it a never-ending cycle.

How do I know when to replace my brake fluidBy measuring the amount of copper ions that are in your brake fluid, you will be able to tell how many inhibitors are left in the fluid.  The more corroded the copper is, the less inhibitors there are, and therefore the greater the need for you to replace the brake fluid.

How do I measure the amount of copper ions in my brake fluid?  You can measure the amount of copper ions by using a special test strip.  You simply dip the strip in the fluid and then wait for it to change color.  According to MAP (Motorist Assurance Program) guidelines, if the color indicates that there is 200 PPM or more of copper ions in the brake fluid, the fluid is required to be replaced.  This is because studies show that at 200 PPM, the inhibitors have lost their ability to protect the braking system from future corrosion.  Our past blog post, How to Check Your Brake Fluid, explains how to check the brake fluid level.  You can follow the beginning steps to locate the brake fluid in your car.


If you find you need to replace your brake fluid, CALL US TODAY at (301)419-2700 and ask for one of our service advisors to schedule your service or schedule it here.

Any questions? Let us know in the comments section below.

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