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Summary
  • A brake flush is the process of replacing your vehicle’s brake fluid.
  • It can cost anywhere between $113 and $127 to have a professional perform the procedure.
  • Aside from replenishing brake fluid, the brake flushing process also involves inspecting the entire brake system for leaks and the condition of its parts.

Want to do a brake flush but you’re not sure what the process might involve? Read on.

What Is a Brake Flush?

Brake flushing is the process of replacing all of your vehicle’s brake fluid. Most OEM manufacturers don’t specify an interval for brake fluid flushes. Check your owner’s manual maintenance schedule to see if there’s an OEM interval recommended.

How Much Does a Brake Flush Cost?

The cost of a brake flush service varies according to factors like your vehicle’s specifications and brake fluid change cost. A good rule of thumb is to expect a price tag ranging from $113 to $127 if you have it done at a shop. Some shops will charge a lot more in your area. If you’re wrench smart and patient, you can do it yourself. More about that in a minute.

mechanic flushing brake fluid
Brake flushing is the process of replacing all of your vehicle’s brake fluid and the various contaminants that have accumulated in the brake lines over months or even years of use.

Why Does Your Car Need a Brake Flush?

The force transmitted by the brake fluid can be as high as 3,000 psi during panic stops. Fluid pressure applies the calipers (disc brakes) and wheel cylinders (drum brakes), which in turn converts the kinetic energy in the spinning drums or discs connected to the car wheels into heat energy, stopping or slowing the car.

Brake fluid can become contaminated with moisture and copper over time, which reduces its performance by changing its boiling point. Brake fluid, like engine coolant, has a very high boiling point. That’s why when you get brake fluid on your hand it feels warm.

Brake fluid, like engine coolant, has a very high boiling point. That’s why when you get brake fluid on your hand it feels warm.

– Richard McCuistian, ASE Certified Master Automobile Technician

What Happens During a Brake Flush?

Flushing the brake system professionally is sometimes done with a brake fluid exchange or flush machine.

See also  What Happens to Your Vehicle When You Slam on the Brakes Often?

Many shops, however, don’t use a fluid flush or exchange machine. They simply raise the vehicle (if you decide to do this yourself, raise the vehicle safely and support it on jack stands). They then install a tightly fitting rubber hose on the bleeder at each wheel, run the hose into a bottle at each wheel so that the end of the hose is submerged in a small amount of fluid already in the bottle (this prevents air ingestion during the flushing process). Afterwards, they loosen all four bleeder screws and add fluid while having an assistant pumping the brake pedal.

Keeping the reservoir full during this process is of paramount importance to prevent air from getting into the brakes. Have plenty of brake fluid on hand. You can buy it by the gallon at parts stores, usually for about $20 a gallon. Get the right kind for your car (check your owner’s manual)

brake flush using a olastic bottle
This photo illustrates one reliable way of keeping fluid in the reservoir for extended periods of pumping the brakes during the brake flush procedure. This works well because you can watch the fluid level in the bottle and refill it when it gets low. Make sure to wash the bottle out a couple of times with a small amount of brake fluid to get rid of any moisture before you do this.

This method replaces the old brake fluid with new brake fluid. Don’t use brake fluid flush chemicals because the ABS hydraulic control unit can be damaged that way. When the fluid entering the bottles is clear, the brake fluid flush is complete. | Image Source: Richard McCuistian

Replenishing brake fluid and removing contaminants aren’t the only things that happen during a brake flush. A professional will inspect your car for brake fluid spills and leaks as well as brake hardware, brake line condition, pad and shoe wear, etc. They may check for ABS diagnostic trouble codes and proper operation of the brake warning light. If they find a leak, they will need to repair or replace the faulty part causing it, but that’s usually done before brake fluid flushing procedures begin.

Finally, the professional technician will put your car through a test drive to make sure that the brakes are working properly.

Are Brake Flushing and Brake Bleeding the Same?

You have probably heard about brake bleeding or even performed the job yourself. It is not the same as a brake system flush. While they have superficial similarities, bleeding your brakes and flushing the brakes are different processes.

See also  Leaking Brake Fluid Causes and Dangers

The main reason for bleeding brakes is to remove air in the brake lines. Brake fluid won’t compress, but air will, and with air in the lines, the pedal will feel spongy. If there’s enough air, the brakes won’t even stop the car.

Brake bleeding ABS systems sometimes require connecting a high-end scan tool and executing a procedure. This isn’t true with all ABS systems, but bleeding the wheels in the proper order is extremely important, so make sure you have the proper information on that. One important thing to remember is to never assume you know the right order. Bleeding wheels in the wrong order can leave air in the system.

Compared to brake flushing, brake bleeding isn’t done to replace the entire supply of brake fluid. Once the air bubbles have been expelled from the brake lines, the mechanic stops bleeding the brake in question. A considerable amount of old brake fluid might remain in the brake system after the bleeding process.

Take note that while bleeding the brakes you might still have air moving through the system that hasn’t yet made it to the bleeder(s), so you may see fluid without air being pushed out before all the air is actually worked out of the system.

mechanic bleeding brakes
Brake bleeding, on the other hand, is the process of removing air bubbles in the brake lines to bring back the brake fluid’s compressibility.

When Should You Schedule a Brake Flush For Your Car?

Consult your owner’s manual for the best time to bring your car in for a brake flush. Most vehicles don’t list a brake flush interval, and flushing the brakes isn’t nearly as important as changing the engine oil. If you can’t locate your manual, visit the manufacturer’s website or a reliable online source to find out the right interval.

Diagnosing Copper and Water Contamination

If you have plenty of DIY automotive troubleshooting experience, you can try diagnosing your brakes for copper and water contamination to see if the vehicle needs a brake flush.

Unless your brake system has been compromised by leaving the master cylinder cap off or pouring the wrong kind of fluid (like oil or power steering fluid) in the master cylinder reservoir, brake fluid contaminants are typically going to be copper and water. Brake fluid is hygroscopic, meaning, it absorbs water. Copper comes from the allow used to coat the inside of the brake lines.

See also  How Much Brake Fluid Do I Need? Plus Other FAQs
mechanic checking moisture in the brake fluid
To check for moisture (water) that has been absorbed by the brake fluid, you can measure the brake fluid voltage, believe it or not. More than 0.30 volts measured this way indicates enough moisture to necessitate flushing. | Image Source: Richard McCuistian

Copper contamination can be measured using dip strips available online. There are double-ended strips, and you can check your coolant and your brake fluid with the same strip. The brake fluid dip strip will change color based on how much copper is in the fluid and there is a color chart on the package to interpret the results. These strips are available online for a very reasonable price.

What to Do If Flushing the Brakes Doesn’t Work

If you flush your brakes but the fluid gets contaminated not long after, there might be something wrong with the brake master cylinder or another braking system part. Take your vehicle to a mechanic for a diagnosis. If you need to replace a part, look no further than CarParts.com.

Our auto parts are vetted by a team of industry professionals to guarantee both quality and durability. You also won’t have to wait too long to receive your order. Because our warehouses are strategically located all over the US, you can expect your new brake part in as fast as two business days.

All you need to do is use your mobile device or computer to visit our website. Input your ride’s details into the vehicle selector to view compatible components. Then, use the search filters to find the ones that match your preferred brand, price, features, and more.

Repair your brake system in no time. Check out our catalog and shop now!

About The Authors
Written By Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Reviewed By Technical Reviewer at CarParts.com

Richard McCuistian has worked for nearly 50 years in the automotive field as a professional technician, an instructor, and a freelance automotive writer for Motor Age, ACtion magazine, Power Stroke Registry, and others. Richard is ASE certified for more than 30 years in 10 categories, including L1 Advanced Engine Performance and Light Vehicle Diesel.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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