Mastering Brake Fluid Flush: Tips, Signs, and Step-by-Step Guide

The brake system of your vehicle comprises numerous components, many of which are susceptible to wear and tear. Parts such as the wheel cylinders, calipers, and rubber used in the master cylinder valves gradually break down. The small particles that break away from these components eventually settle in the brake fluid. Therefore, brake fluid flush is necessary after a specific interval.

Brake Fluid Flush

A good rule of thumb is to schedule a brake fluid flush approximately every 48,280 kilometers (or 30,000 miles) or every two years. 

Exposure to air, particularly from the master cylinder reservoir, allows your brake fluid to absorb moisture. Over time and across thousands of miles, this process gradually transforms the fluid’s color from clear to a brownish hue, indicative of internal corrosion within the brake system.

As the brake fluid accumulates more water, it reduces the boiling point of the brake fluid and escalates its corrosiveness. This article mainly how to flush the brake fluid and when you should do it.

What is a Brake Fluid Flush?

A brake fluid flush refers to the procedure of replacing old fluid in the brake system with new, uncontaminated fluid. This process is crucial for maintaining the efficacy of your brakes and should be carried out every two years or every 30,000 miles.

As you depress the brake pedal of your vehicle, the brake fluid is transferred from the master cylinders through the brake lines, pushing the brake piston, which then puts pressure from the pads to the brake rotor.

For a drum brake system, the brake fluid helps the set of brake shoes to push against the brake drum, thereby stopping the wheel’s motion.

Over time, the brake fluid becomes contaminated, it doesn’t work efficiently and reduces the performance of the braking system. Therefore, the flushing of the brake fluid is very important to ensure the optimum performance of the braking system.

Signs That You Need a Brake Fluid Flush

If you observe one or more of the below-given symptoms, it means that you need to flush your brake fluid.

1) Bouncy or Spongy Brake Pedal

Spongy Brake Pedal

A bouncy or spongy brake pedal is one of the clear signs that you need to flush or change your brake fluid.

Furthermore, if your brake pedal is fully pressed before the vehicle begins to stop or decelerate, it suggests that it’s time to change the brake fluid.

Air may infiltrate the brake lines over time because of insufficient brake fluid, leading to the feeling of spongy brakes. This situation can be both alarming and potentially hazardous.

2) Illuminated ABS Light

ABS Light

The illumination of the ABS (Anti-lock Braking System) light on the dashboard is often a result of inadequate or contaminated brake fluid. This signifies that the ABS system of your vehicle, which is designed to prevent the wheels from locking up and losing traction while braking, is not functioning correctly. It’s imperative to address this issue promptly to avoid accidents.

Read More: ABS Light Meaning and Causes

3) Poor Performance of Braking System

Brake System Warning Light

To ensure a vehicle can slow down or stop quickly in emergencies, it’s important for the brake system to be both quick and responsive. If there are any issues that prevent a vehicle from decelerating or stopping effectively, it means the brakes need to be serviced.

The issue could be attributed to worn brake pads, warped rotors, or defects in other components of the brake system.

Concurrently, other underlying issues, such as faulty shocks, worn-out tire treads, or bad struts, may also lead to inefficient braking. However, these problems might also suggest a need for fresh, clean brake fluid.

By conducting a thorough examination of the brake system, a mechanic may determine the most effective solution to restore the performance of the braking system.

Read More: Causes of Brake System Warning Light

4) Strange Sounds While Braking

Grinding Noise, signs you need brake fluid flush

An unusual sound occurring when the brake is applied is also one of the clear symptoms of contaminated brake fluid, and you need to flush it. Grinding or scraping sounds should also serve as immediate red flags.

Read More: Causes of Squeaking Noise

5) Burning Smell

burning Smell

If you detect a burning smell while applying brakes, it’s possible that your vehicle’s brake fluid has overheated. In such situations, it’s advisable to safely stop the vehicle and let the engine cool down.

Promptly consult with a mechanic and schedule a service appointment as soon as possible. Continuing to drive with overheated brake fluid may lead to far more severe complications, such as complete brake failure.

How to Flush the Brake Fluid

To flush or change the brake fluid of your vehicle, follow the below-given steps:

1) Park the Vehicle

Park the Vehicle, How to Flush the Brake Fluid

The first step is to park the vehicle in a safe location and turn off the engine. Now, let the engine cool down. Also, apply the parking brake. 

2) Lift the Vehicle

Lift the car

Use a jack to lift the vehicle and place it on the jack stands. Place a stop behind the tires to prevent it from rolling.

3) Remove the Old Fluid

Brake Master cylinder

Now, locate the master cylinder. You can consult your vehicle’s service manual to easily find the master cylinder reservoir.

After locating the reservoir, thoroughly drain the old fluid from the master cylinder reservoir. You can do this through several methods, such as using a transfer pump with a tube, a small siphon pump, a turkey baster, or a large syringe.

These tools allow for easy removal of all the fluid from the master cylinder while the vehicle is turned off and with no pressure applied to the brakes. 

4) Fill the Reservoir with Fresh Fluid

Now, add the fresh fluid to the master cylinder. From this point forward, the process is identical to brake bleeding.

5) Flush the Calipers/Wheel Cylinders

Flushing the wheel cylinders, change the brake fluid

Start by working on the back of the car and getting rid of the old fluid in the rear calipers or wheel cylinders. Continue doing this until all the brown, rusty, old fluid is completely replaced with clear, fresh fluid flowing through the tube.

After that, move to the front of the vehicle and check the master cylinder reservoir each time you bleed a wheel. Make sure to top it up if needed.

6) Top Up the Reservoir

Brake fluid reservoir

Once you’ve finished bleeding all the wheels, proceed to lower the vehicle by utilizing the jack positioned at each corner. Remove the jack stands from the respective corner and gradually lower the vehicle until it reaches the ground.

After lowering the vehicle, top up the reservoir to the fill line. With this step, the process is complete!

How to Change Brake Fluid without Bleeding?

A straightforward way to change brake fluid without having to bleed the system involves using a kitchen meat-basting tool or a pump to remove most of the fluid from the fluid reservoir.

It’s important to ensure that you do not introduce any air into the circuit while extracting the fluid. Once done, fill up the master cylinder with fresh brake fluid.

FAQ Section

Why is a Brake Fluid Flush Important?

Brake fluid has a tendency to attract and absorb moisture from the air. When this happens, it can lead to corrosion of the braking system’s metal parts. This corrosion may cause the metal components to deteriorate and fail quickly, resulting in expensive repairs. To prevent this, a brake fluid flush is performed.

What is Brake Fluid Flush?

The brake fluid flush is a process that involves replacing the old brake fluid in the master cylinder reservoir with fresh fluid, which helps restore the necessary additives, remove impurities, and enhance the brake performance.

What happens if you accidentally put water in your brake fluid?

Introducing water to your brake fluid may pose a significant risk. Water reduces the brake fluid’s boiling point, leading to a phenomenon known as vapor lock (the formation of steam in the system), subsequently causing brake failure. It may also lead to internal rusting and corrosion. If water is inadvertently introduced, an immediate full brake fluid flush becomes absolutely necessary.

How often should you change brake fluid?

Brake fluid changes are a crucial part of vehicle maintenance. A good rule of thumb is to change the brake fluid approximately every 30,000 miles or every two years. 

How do you tell if your car needs a brake flush?

If your brake pedal begins to feel exceptionally mushy or soft, it’s usually a sign that it’s time to flush the brake fluid.

What happens if you don’t flush the brakes?

If you don’t flush the brakes on time, it may cause the metal components to rust and corrode, which can eventually lead to these corroded particles contaminating the brake fluid and leading to the complete failure of the braking system.

How to Change Brake Fluid?

The process of changing brake fluid begins by using a baster to remove the old fluid. This extracted fluid should be deposited into a recycling bottle. Afterward, top up the master cylinder reservoir with fresh brake fluid. Subsequently, drive the car for a few days to allow the fresh fluid to integrate with the old. This procedure should be repeated multiple times over the forthcoming weeks until the fluid in the reservoir maintains a light honey-like color.

Will changing brake fluid improve braking?

Yes, changing brake fluid may enhance the efficacy of your braking system. Over time, brake fluid may gather contaminants, causing the boiling point to decrease and thus compromising brake performance. By flushing the brake fluid, you can restore the braking system’s effectiveness and reaction time. Therefore, it’s generally advised by the vehicle manufacturer to change your brake fluid every two years for optimal performance of the brake system.

How much does it cost to flush a Brake Fluid?

The average cost to flush a brake fluid is from $60 to $130. This cost can vary based on the make and model of your vehicle as well as the labor cost. It’s crucial to remember that routine maintenance can prevent more costly repairs in the future.

How long does a brake fluid flush take?

The duration of a brake fluid flush usually takes around 25 minutes to 1 hour, although the exact timing can fluctuate according to the tools utilized, the condition of your brake system, and the vehicle model. Complex brake system designs, as well as any existing damage or corrosion, may lengthen the procedure.

Can I flush the brake fluid myself?

In brief, the answer is yes; it is possible for you to perform a brake fluid flush yourself. However, this task necessitates good mechanical knowledge and correct disposal because of the potential environmental impact. To restore the whole performance of your braking system, it’s typically advisable to entrust this job to professional mechanics.

Can you add new brake fluid to the old one?

Though it’s technically possible to add new brake fluid to old, this practice is not advisable. The blending of old and new fluid may weak the pollutants, but it doesn’t remove them, potentially affecting the efficiency of the brake system. Conducting a complete brake fluid flush remains the best course of action.

How many times can you bleed the brakes?

There’s no set maximum number of times to bleed your brakes. This process should be carried out until all air has been purged from the brake lines, guaranteeing that only fluid remains. Nonetheless, if you find yourself needing to bleed the brakes frequently, it could signal an issue with your braking system that needs a professional examination.

How long does it take to change brake fluid?

If you just need to change the brake fluid, a skilled mechanic should be able to finish the job in about 14 to 30 minutes.

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