If your brake pedal feels spongy or you often hear unusual noises when braking, you might be due for a brake fluid flush.
What is a brake fluid flush?
It’s a service that removes old or contaminated fluid from the brake system and replaces it with fresh fluid. This helps keep your brakes healthy, responsive, and safe.
Curious about how it’s done and what it might cost?
In this guide, we’ll explain why brake fluid flush is necessary and how it’s performed. We’ll also discuss the average cost of brake fluid flush services, so you know exactly what to expect before scheduling this service.
This Article Contains:
- Why Is a Brake Fluid Flush Necessary?
- 6 Symptoms That Indicate You Need a Brake Fluid Flush
- What Happens During a Brake Fluid Flush?
- How Much Does a Brake Fluid Flush Cost?
- How Often Do You Need a Brake Fluid Flush?
- 5 FAQs about Brake Fluid Flush
Let’s jump right in.
Why Is a Brake Fluid Flush Necessary?
Your brake system consists of several interconnected components. Many of these parts are connected by brake lines and hoses, which use brake fluid to transmit and amplify the force from your brake pedal.
Here are the two most essential functions that fresh brake fluid performs:
1. Maintains Brake Fluid Quality
Due to age and repeated use, it’s common for brake fluid to become contaminated with debris, metal, or rubber from various parts of the brake system.
This can limit the pressure-transmitting capacity of the hydraulic fluid, reducing your stopping power. Ultimately, as contamination becomes excessive, your hydraulic brake system may stop working.
What’s more?
Brake fluid also contains additives like corrosion inhibitors, anti-rust components, and pH balancers that protect your car’s components. Over time, these additives become depleted, allowing corrosion to accumulate inside the brake system.
Adding new fluid helps restore additive package levels, remove contaminants, and ultimately improve brake performance.
2. Prevents Moisture Build Up
Brake fluids are hygroscopic, meaning they tend to absorb moisture. The moisture absorbed by brake fluid can lead to corrosion of several metal parts (like the brake caliper, brake master cylinder, or brake rotors) and disrupt their functioning.
Performing a brake fluid flush eliminates the moisture-laden fluid, thereby preventing corrosion and ensuring optimal health of a brake system component. This is especially important when it comes to the Anti-lock Braking System (ABS) and other traction control components.
Why?
The ABS and traction control components are hyper-sensitive to moisture. If these components are exposed to contaminants from the old brake fluid for extended periods, they may become damaged, leading to brake failure and potentially costly repairs.
It’s clear that brake fluid flushes are very helpful.
But how do you know when your vehicle needs a brake fluid flush service?
6 Symptoms That Indicate You Need a Brake Fluid Flush
Here are some signs that call for a brake fluid change:
1. Brake Fluid Leak
If you notice a brake fluid leak, you may require an immediate brake fluid flush, as it reduces the braking force transmitted through the brake line.
To confirm your brake fluid level, check the brake fluid reservoir. Typically, you’ll find the brake fluid reservoir near the engine compartment; however, if you don’t feel confident about confirming a brake fluid leak on your own, you can call a mechanic for help.
2. Contaminated Brake Fluid
Clean brake fluid typically appears as a light golden, light brown, amber, or transparent color.
However, if it looks dark or dirty, you might need a brake fluid flush. This can occur due to brake fluid aging or contamination from rubber, rust, or other debris that clogs the brake line.
If this is the case, take your car to an auto repair shop for a brake fluid flush service as soon as possible.
3. Brake Pedal Feels Soft or Spongy
At times when you’re applying the brakes, you might feel that your brake pedal is spongy.
If brake fluid absorbs too much moisture, it forms air pockets containing water vapor when these fluids get exposed to high temperatures. These air pockets reduce the effectiveness of your vehicle’s brakes, leading to a soft-feeling brake pedal.
When this happens, your brakes won’t respond as you want them to and may cause potential brake failure, leading to significant safety hazards. If you notice a spongy pedal, request an immediate brake system inspection.
4. Poor Braking Response
Your brakes should respond immediately when you press the pedal. If there’s a delay or the brakes feel sluggish, it could be a sign that your brake fluid is old or contaminated and needs to be flushed.
These issues could also stem from worn brake pads, wrapped rotors, or other components. Have a mechanic inspect your system to determine whether a brake fluid flush is needed or if another repair is required.
5. The ABS Light Turns On
In some cars, the ABS warning light on the dashboard gets activated when you need a brake flush. However, remember that the ABS light doesn’t just turn on if you have bad brake fluid or a low brake fluid level; it can also activate due to :
- A malfunctioning ABS module
- Broken wheel speed sensors
- A turned-off ABS
For safety, it’s recommended to have a mechanic diagnose the cause of an activated ABS light and address the underlying issue.
6. Strange Noises or Burning Smells
Squealing, grinding, or scraping noises, as well as a burning smell after heavy braking, can indicate contaminated or overheated brake fluid. Driving with burnt or contaminated brake fluid can lead to serious problems, including brake failure.
If this happens, safely pull over, let your brakes cool, and call a mechanic to perform the flush.
What Happens During a Brake Fluid Flush?
Performing a brake fluid flush requires proper tools and expertise to fully drain the old fluid, prevent air from being introduced, and ensure the brake system functions properly. Incorrect handling can lead to reduced braking performance or system damage.
For best results, it’s recommended that you take your vehicle to an auto service shop or request a mobile mechanic to come over to your location for brake service.
During a brake fluid flush, your mechanic would:
- Locate the brake fluid reservoir.
- Drain out the contaminated and old brake fluid.
- Clean out any debris left in the braking system.
- Check whether any other brake components, such as the brake caliper, brake master cylinder, brake pads, or brake rotors, require replacement.
- Add new brake fluid.
- Remove any trapped air bubbles in the brake line using a bleeder.
- Check if the brake system is working correctly.
Wondering how much it costs?
Let’s find out.
How Much Does a Brake Fluid Flush Cost?
The cost of a brake fluid flush ranges between $60 and $200. This estimate includes:
- Fluid cost: $10 to $30 per quart (most cars require about 1 quart of brake fluid)
- Labor: $50 to $170
However, the brake fluid flush price may vary depending on your choice of fluid and the labor costs in your area. It can also depend on your vehicle’s year, make, model, and engine type.
Need an accurate estimate for your vehicle make and model?
Just fill out this online form.
With the costs covered, it’s time to consider how frequently this service should be performed.
How Often Do You Need a Brake Fluid Flush?
Generally, most professional mechanics recommend getting your brake fluid flushed every 2-3 years or 30,000 miles. For an exact service schedule, it’s best to check your vehicle owner’s manual.
However, you may need frequent brake fluid flushes if you often drive in stop-and-go traffic or use your brakes aggressively.
TIP: While getting a brake fluid flush, consider getting a tire rotation, since your mechanic is already working with your wheels. It’s also a good idea to have a mechanic check your brake fluid levels during an oil change service.
Got more questions?
Check out these FAQs.
5 FAQs about Brake Fluid
Here are the answers to some commonly asked questions about brake fluid:
1. What Does Brake Fluid Do?
Brake fluid amplifies and transmits the force you apply to the brake pedal. When you press the pedal, this force activates the brake master cylinder, which then pushes the brake fluid through the brake lines to the brakes at each wheel.
If your car uses a disc brake system, a plunger inside the master cylinder pushes pressurized fluid into the brake caliper pistons. These hydraulic pistons then squeeze the brake pad against the wheel rotor, creating friction that helps stop the car.
In the case of a drum brake assembly, pressurized brake fluid acts on the wheel cylinder, which pushes a set of brake shoes against the drums to stop the wheels.
2. How Do You Choose the Right Brake Fluid for Your Car?
To choose the correct brake fluid, always refer to your vehicle’s owner’s manual or the cap on the brake fluid reservoir for the recommended DOT (Department of Transportation) type.
Here are the options available:
- DOT 3 is a basic glycol-based fluid suitable for everyday driving.
- DOT 4 has a higher boiling point, which makes it ideal for vehicles with ABS, Electronic Brakeforce Distribution (EBD), and for driving in hot or hilly conditions.
- DOT 5.1 is a high-performance glycol-based fluid designed for use in sports cars, high-performance vehicles, or in extreme conditions.
- DOT 5 is silicone-based, making it ideal for cars that are exposed to extreme temperatures or require storage for extended periods. You should never mix it with DOT 3, 4, and 5.1, as it can cause the seals to fail and damage the brake system.
3. What’s the Difference Between a Brake Fluid Flush and Brake Bleed?
A brake fluid flush completely removes old fluid from the brake system and swaps it with new, clean fluid. This clears out moisture and contaminants from the lines, calipers, and master cylinder, helping your brakes stay responsive and reliable.
Bleeding, on the other hand, removes air bubbles trapped in the brake lines, which can make the pedal feel soft or spongy. It restores proper brake feel and provides consistent braking performance.
4. How Long Does a Brake Fluid Flush Take?
At a professional shop, a brake fluid flush usually takes less than an hour. But if you’re doing it yourself and are unfamiliar with the process, it may take longer.
5. What Happens If You Add Water to Brake Fluid?
Water in the brake fluid is hazardous. It lowers the fluid’s boiling point, which can cause vapor lock (steam forming in the brake system) and ultimately lead to brake failure. It can also allow rust and corrosion to accumulate inside the system.
If water gets into your brake fluid, call a mechanic to perform a complete brake fluid flush immediately to restore safe braking.
Trust AutoNation Mobile Service for Brake Fluid Flush
Clean, fresh brake fluid is essential for the safe functioning of your vehicle’s braking system. Regular flushes help prevent corrosion, remove contaminants, and ensure your brakes respond quickly and effectively when you need them.
Fortunately, carrying out a brake fluid flush for your vehicle is super convenient with AutoNation Mobile Service. We’re available seven days a week and back every service with a 12-month, 12,000-mile repair warranty.
Book an appointment online and our mobile mechanics will come to you, ready to perform a brake fluid flush service.