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Why did the Mechanic Say I Need my Brake Fluid Flushed?

Updated: Jan 18, 2021

What is a brake fluid flush and why does my car need it regularly? The braking system on your vehicle is a closed hydraulic system (meaning it is operated using fluid). Brake fluid is hygroscopic which means that it absorbs moisture from the air. Over time, this moisture causes the fluid to corrode inside the brake lines. If you get too much corrosion, you could actually cause a blockage. Think of it like plaque inside your arteries. If you get too much plaque you could cause a blockage to your heart or brain.

The other thing moisture can do to your braking performance, is it can cause a "spongy" feel in the brake pedal. This means that when you press on the brake pedal, you do not get a firm feeling back and you may not stop as quickly and efficiently as possible.

Another reason to change your brake fluid regularly, is because outside contaminants can get inside the reservoir or inside the brake lines. Brake fluid is clear, so if you look at your brake fluid reservoir (should say something along the lines of "use only DOT 3 brake fluid" on the cap) and the fluid is NOT clear, it's probably time for a flush. Keep in mind that the brake fluid level should live in between the "Low/Min" line and the "High/Max" line. Unless it is below the minimum level, you do NOT need to add fluid as the level will rise when you have your brake pads replaced, and you don't want it to overflow.

The recommended interval for a brake fluid flush is usually every 3 years or 30,000 miles. You should never use a bottle of brake fluid that has previously been opened. The type of brake fluid your specific vehicle uses can be found in your owner's manual or usually on top of the brake fluid reservoir cap, inside the engine compartment. It will usually be DOT 3 or DOT 4 depending on your vehicle.

If you have a friend that can help you step on the brake pedal, it is pretty simple to perform a brake fluid flush yourself, just using the tools from your spare tire kit (to remove the wheels) an old bottle, some tubing, and the correct size wrench. Watch the video below for more inspiration and let me know if you have questions:

It is incredibly important not to get any air in the brake system. After performing a brake fluid flush, make sure to depress the pedal many times before driving (with the vehicle running and in Park) to make sure that you have a firm pedal. Go on a short test drive without traffic and remember you have your emergency brake as a backup if for any reason you do find an air bubble.

The brake system is a very important system on your vehicle, so if you do not feel comfortable, or you have questions, please make sure to consult a professional.

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