Brake System Bleeding And Flushing For All Vehicles: What & Which

Maintaining your brakes is critical for the safety of you and other drivers on the road. Brake pads and rotors must be replaced regularly, but a brake bleed or flush could also be necessary. So what’s the difference?

When a vehicle needs a brake bleed, brake fluid is drained from the master cylinder and bled from each wheel until all air bubbles are forced out of the lines. This ensures that your brakes perform precisely as they should. A brake flush removes old fluid from the system and introduces new fluid. This keeps corrosion at bay, slows down internal damage, and improves overall performance.

It’s usually done when there’s worn lining in hydraulic components like ABS systems or the master cylinder or if there’s been any servicing of hydraulic components. Knowing when to perform either is key to ensuring you always keep your brakes in tip-top shape. Dig into and learn more about this fact.

Difference Between a Brake Bleed and Flush:

A brake bleed and a brake flush are two methods to ensure maximum braking power in your vehicle. A brake bleed involves pumping fresh brake fluid into the system, thus eliminating any air bubbles that may have formed.

Air bubbles can interfere with pressure transmission within the braking system, reducing effectiveness. If you’ve noticed that your brakes are not as effective as they used to be, it is likely recommended that you will need to perform a brake bleed.

On the other hand, a brake flush involves draining all the current fluid from the brake lines and replacing it with new fluid. While a brake bleed addresses potential air bubbles inside the system, a flush removes all existing contaminants from the old fluid, which could reduce efficiency or even introduce new problems to your brakes.

It is important to note that when performing either a bleed or a flush on your brakes, ensure you never mix fluids such as DOT 3/4 or DOT 5, as this can cause compatibility issues and damage certain components of your braking system.

How Does Brake Fluid Go Bad?

Brake fluid is essential to properly functioning your vehicle, as it helps create the hydraulic pressure necessary to apply the brakes. Over time, however, brake fluid can start to break down and go bad.

This deterioration can be caused by several things, including air or moisture absorbed in the fluid, dirt, and debris from other system parts and frequent exposure to high temperatures.

When brake fluid has gone bad, it will reduce your brakes’ effectiveness and make it more difficult for you to stop quickly and safely. To prevent this from happening, you should check your brake fluid regularly (at least twice a year) for signs of wear and tear.

If you notice any change in color or viscosity, have it checked out immediately by a professional mechanic as soon as possible before it becomes an issue.

Additionally, other components, such as brake lines, should be inspected frequently to confirm they are free of any obstructions that could lead to contamination and trigger a need for replacement brake fluid sooner than expected.

Which One is Better?

Generally speaking, when servicing your brakes, you need not introduce air into the system or allow the fluid level to become completely drained. Your best bet is usually to follow what the manufacturer of your vehicle recommends regarding maintenance. For example, if there’s no recommendation for flushing your brakes, it might not be necessary.

In this scenario, if you’ve been keeping up with recommended service intervals and changing out the brake fluid regularly – usually every 30,000 miles or so – the fluid looks clear and free from contaminants. Bleeding your brakes may be all that’s needed.

In contrast, if you haven’t kept on top of your car’s maintenance schedule and notice that the brake fluid has become murkier, then it might be time for a full flush. Always check what’s suggested in your owner’s manual or service booklet first.

Brake Bleeding Frequency

The frequency with which brakes need to be bled depends on the type and condition of your vehicle. There’s no need to bleed for typical OEM braking systems unless you open the system for repair or replacement. For everyday town/ highway driving, it isn’t necessarily required either. However, on certain European cars, quarterly brake fluid replacement is necessary.

Additional bleeding may be recommended if you drive in a sporting manner or put your car through high-speed braking events or driver schools/lapping sessions – these would be ideal times to do a thorough ‘start-of-the-season maintenance check and brake flush. Regardless of your circumstances, always consult manufacturer instructions or your service center when determining how often you should bleed your brakes.

Frequently Asked Questions [FAQs]

1. Do Vehicles Need Brake Fluid Flush?

Yes, vehicles must have a brake fluid flush performed occasionally to ensure the brakes function as safely and effectively as possible. The brake system is an incredibly important part of any vehicle, and keeping it in top condition is essential.

Brake fluid flushing is a process that involves removing the old and contaminated brake fluid from the system and replacing it with fresh, clean fluid. This helps to prevent wear and tear on the system, as well as improve the overall performance of the brakes.

2. How Often Should You Flush Brake Fluid?

The frequency you should flush your brake fluid will depend on your vehicle type and how often it is used. Generally, it’s recommended that all vehicles have their brake fluid flushed at least once a year and more often if the vehicle is used for a lot of heavy-duty driving.

It’s also important to check with the manufacturer’s guidelines for your vehicle, as this may provide specific instructions for how often you should flush the brake fluid.

3. What Is The Benefit Of Brake Flush?

The benefit of a brake flush is that it helps to improve the overall performance of your vehicle’s braking system. It is important to flush the brakes periodically to keep them working efficiently and effectively.

A brake flush removes contaminants, dirt, or air bubbles that may have built up inside the brake lines over time. This can help reduce brake noise and ensure brakes perform at peak capacity. Additionally, a brake flush ensures that your safety is taken seriously by ensuring the brake system works optimally.

4. How Often Is A Brake Flush Needed?

Typically, a brake flush should be performed every two years or 24,000 miles. However, this can vary depending on the type of vehicle and its braking system. Brake fluid is hygroscopic, which means it absorbs moisture over time.

This can cause corrosion to occur within the braking system. In addition, as brake fluid gets older, it becomes contaminated with dirt and other debris from the braking system. This can lead to decreased brake performance and potentially dangerous situations.

5. What Is Special About All Brake Fluids?

Brake fluids are special in that they are designed to provide lubrication, cooling, and protection against corrosion of the internal components of the brake system. All brake fluids consist of a certain base fluid and a range of additives for specific purposes.

Common types of brake fluid include glycol-ether-based fluids (DOT 3, DOT 4, and DOT 5.1) and mineral oil-based fluids ( DOT 5). The DOT rating indicates the brake fluid’s boiling point, or how hot it can get before it starts to boil.


Brake system bleeding and flushing are important processes that help keep your vehicle’s brakes in optimal condition. The frequency with which you should bleed your brakes will depend on the type of vehicle, how often it is used, and other factors. Additionally, brake fluid flushes should be performed regularly to remove contaminants or air bubbles from the system. For best results, always consult manufacturer instructions to determine the correct procedure for your vehicle.

John D. Archer

John D. Archer is a mechanical engineer and writer based on the area of automotive accessories at, A resident expert and professional, John is passionate about all things automotive and loves to share his knowledge. He has good experience in all kind of automotive accessories. He has worked as a chief mechanical engineer in some reputed automotive garage firm.