Is a brake fluid flush really necessary?

Brake fluid is a vital component of any vehicle’s braking system. Over time, brake fluid can become contaminated and degrade, which can lead to a decrease in braking performance. This has led some mechanics to recommend periodic brake fluid flushes, but is this service really necessary? In this article, we’ll examine the purpose of brake fluid, look at the recommended brake fluid change intervals, discuss symptoms of contaminated fluid, and provide tips on deciding if you really need a brake fluid flush.

What is brake fluid and what does it do?

Brake fluid is a hydraulic fluid that transmits pressure from your brake pedal to the brake calipers, forcing them to clamp down on the rotors and stop your vehicle. Here are some key functions of brake fluid:

• Transmits pressure: As you press the brake pedal, brake fluid carries that pressure through the brake lines and hoses to the calipers.
• Lubricates components: Brake fluid keeps internal brake components like caliper pins lubricated to prevent sticking and binding.
• Prevents corrosion: Brake fluid contains corrosion inhibitors that help prevent degradation of brake system components.
• Withstands high temperatures: Brake fluid is designed to withstand the high temperatures generated during braking without boiling.

Using the correct type of brake fluid designed for your vehicle’s braking system is critical for safe, effective braking performance.

What are the recommended brake fluid change intervals?

Brake fluid change intervals vary by vehicle make, model and year. Here are some general guidelines on typical brake fluid change recommendations:

• 2-3 years: Most domestic vehicles recommend flushing the brake fluid every 2-3 years. This includes models from GM, Ford and Chrysler.
• 3 years: Asian vehicles from Toyota, Honda, Nissan and others typically advise brake fluid flushes every 3 years.
• 2 years: European makes like Mercedes, BMW, Audi and Volkswagen commonly call for brake fluid renewal every 2 years.
• 3-5 years: Some newer vehicles can go slightly longer between changes, usually between 3-5 years.

These are general time-based recommendations only. You should always consult your vehicle owner’s manual for the brake fluid change interval specific to your make and model.

What happens when brake fluid becomes contaminated?

Over time and use, brake fluid can become contaminated through exposure to water, dirt and high temperatures. Here are some potential effects of contaminated brake fluid:

• Corrosion: Water-contaminated brake fluid can corrode brake lines, calipers and other components.
• Reduced lubrication: Contaminants diminish the fluid’s lubricating properties, leading to sticking brake parts.
• Lower boiling point: Water contamination lowers the fluid’s boiling point, increasing the risk of vapor lock.
• Compressor damage: In vehicles with antilock brakes (ABS), dirty fluid can damage the ABS pump and valves.

These effects can gradually reduce braking performance and increase the risk of complete brake failure. That’s why routine brake fluid renewal is essential.

What are the symptoms of contaminated brake fluid?

Here are some signs that suggest your brake fluid may be contaminated and in need of replacement:

• Spongy brake pedal: If the pedal feels soft or sinks to the floor, fluid may be leaking or contain air bubbles.
• Delayed braking: Braking action seems sluggish or unresponsive.
• grinding or squealing: Contaminated fluid increases wear and corrosion.
• Leakage: Look for fluid leaks around brake lines, calipers and the master cylinder.
• Discolored fluid: Healthy fluid is transparent with a light amber color. Dark brown fluid indicates contamination.

If you notice any of these warning signs, have your brake fluid tested and changed if necessary.

When is the best time to flush brake fluid?

The ideal time for a brake fluid flush is when you’re having other brake service performed, such as brake pad replacement. This allows the technician to inspect the entire system. It also avoids the extra labor charges associated with an isolated brake fluid exchange. For example, combining a fluid flush with a regular brake pad swap can minimize total costs.

Can you change your own brake fluid?

With some mechanical ability and the right tools, you can perform a DIY brake fluid flush. Here are the basic steps involved:

1. Raise and secure the vehicle.
2. Locate the brake fluid reservoir under the hood.
3. Use a turkey baster to remove old fluid from the reservoir.
4. Refill with new, clean brake fluid.
5. Repeat process until the fluid runs clear.
6. Bleed the brake lines.
7. Test brake pedal for proper operation.
8. Dispose of old fluid properly.

If you’re unsure about doing it yourself, it’s best to have a professional handle the brake fluid exchange.

How much does a brake fluid flush cost?

Brake fluid flush costs vary by location and shop. On average, you can expect to pay somewhere in these ranges:

Service Provider	Typical Cost Range
Dealership	$120-$220
Chain shop (Midas, Meineke)	$80-$150
Independent mechanic	$60-$120

Combining a brake fluid exchange when you’re already paying for brake work can significantly reduce the total cost.

Can you flush brake fluid yourself?

It’s technically possible to DIY a brake fluid flush if you have some mechanical knowledge and experience. However, there are some important safety risks to consider:

• Brake bleeding tools required – You’ll need a brake bleeder tool to bleed the air out of the lines after the old fluid is removed. Without proper bleeding, air bubbles can lead to brake failure.
• Risk of spills – Brake fluid can easily spill during a DIY flush, damaging paint and other surfaces.
• No brake inspection – A pro fluid exchange includes a visual inspection for leaks and damage.
• Improper disposal – Used brake fluid must be disposed of properly to avoid environmental harm.

Overall, without the right equipment and experience, attempting to flush your own brake fluid can be challenging and risky. For most drivers, it’s safest to have a professional shop perform the brake fluid renewal.

How long does a brake fluid flush take?

On average, you can expect a complete brake fluid flush service to take:

• 1-2 hours at a repair shop
• 2-3 hours DIY

The actual time can vary based on vehicle make and model. More time is needed for larger trucks and SUVs with bigger, more complex brake systems. The bleed process in particular can be time consuming.

Should brake fluid be clear? What color should it be?

Fresh, uncontaminated brake fluid should have a light amber color. It should appear almost clear. Over time, brake fluid can turn into a dark brown, black or muddy color. This darker discoloration signals that the fluid has become contaminated and should be flushed.

Here are the color stages of brake fluid from freshest to most contaminated:

• Clear with light amber tint – healthy
• Light brown – minimal contamination
• Moderate brown – needs flushing soon
• Dark brown/black – contaminated, flush immediately

If your brake fluid reservoir shows a dark, murky color, you can pull some out with a turkey baster for a closer look. But dark discoloration always calls for a full brake fluid flush service.

Do you need to bleed brakes after flushing?

Yes, bleeding the brakes is a critical final step after a brake fluid flush. This bleed process removes any air bubbles that have entered the hydraulic system. Trapped air in the brake lines can lead to a spongy pedal and reduced braking power.

Bleeding the brakes involves running clean fluid through the system while opening the bleeder valves on the calipers one at a time. This allows air to escape until only bubble-free fluid flows out. Expect a thorough bleed process to add 15-30 minutes after the actual fluid flush.

Can brake fluid damage paint?

Yes, spilled brake fluid can definitely damage automotive paint finishes. The solvents and chemicals in most brake fluid types will dissolve paint on contact. Even a few small drops can eat away the clear coat and underlying paint layers, leaving a dull spot.

Brake fluid spills should be rinsed off paintwork immediately with plenty of water. Avoid using soap or other cleaners. The damage may buff out if treated quickly, but deep stains usually require repainting the affected area.

Using painter’s tape during brake work can help protect vulnerable painted components from accidental fluid spills.

Does a brake fluid flush include bleeding?

A full brake fluid flush service should always include bleeding the brakes as the final step. This crucial process purges any air bubbles introduced during the flush. Trapped air can lead to poor pedal feel, spongy brakes and reduced stopping power.

Unfortunately, some shops attempting to save time will flush the fluid without performing a complete bleed. To ensure your brake system is restored to peak performance, request that any fluid exchange includes a thorough bleed service.

Can you mix different types of brake fluid?

It’s best not to mix different types of brake fluid. Each formulation has different properties designed for specific vehicle braking systems. Mixing fluids can reduce braking effectiveness.

Here are 3 common brake fluid types:

• DOT 3 – Common for most passenger vehicles. Medium boiling point of 401°F (205°C).
• DOT 4 – High performance vehicles. Higher 508°F (265°C) boiling point.
• DOT 5 – Silicone-based. Used in some exotic cars. Very high boiling point.

Always check your owner’s manual for the correct fluid type to use. Mixing DOT 3 and DOT 4 is not recommended but unlikely to cause major issues. However, mixing DOT 5 with anything else will create serious problems.

Can I drive without brake fluid?

You should never drive a vehicle without the proper level of working brake fluid. Operating a car with no fluid, or extremely low fluid, is extremely dangerous and can lead to a total loss of braking ability.

Even just one use of the brakes with the fluid completely depleted can allow air into the brake lines and calipers. Air in the system must be completely bled out in order to restore braking performance.

If your brake fluid is very low, have the vehicle towed to avoid the need to use the brake pedal before topping off the fluid level.

How often should you check brake fluid?

Checking your brake fluid should be part of any routine maintenance schedule. Here are some good rules of thumb for brake fluid checks:

• Monthly – Quick monthly checks ensure the reservoir isn’t abnormally low.
• Oil changes – Check fluid when you change your oil.
• Before long trips – Inspect fluid level before road trips or vacations.
• Seasonal – Brake fluid can slowly decrease in colder weather. Check before winter.

Watch for any signs of leaking or deteriorating fluid quality. Top off the reservoir as needed to maintain the proper level.

Can you use any brake fluid?

No, you should only use the specific type of brake fluid formulated for your vehicle’s make and model. The owner’s manual will indicate the correct fluid type such as DOT 3, DOT 4, or DOT 5.1.

Using the wrong kind of brake fluid can decrease braking performance and damage brake system components. Each fluid has different properties like boiling point, lubrication, and water absorption designed for specific braking systems.

Never use just any fluid in an emergency. Have the vehicle towed to prevent the need to use compromised brakes. Using gasoline, transmission fluid or other fluids in the brake system will create dangerous and expensive problems.

Conclusion

Regular brake fluid replacement is crucial for maintaining optimal braking power. While each vehicle has specific recommendations, most experts suggest flushing the fluid at least every 3 years or 30,000 miles. More frequent renewal may be required by some manufacturers.

Contaminated brake fluid can significantly reduce braking performance and increase the risk of complete system failure. Any signs of deterioration or issues with braking warrant immediate inspection of the fluid.

Although possible to DIY, brake fluid flushes are best performed by a professional technician to ensure thorough fluid replacement and proper bleeding. For safety-critical brake system maintenance, it’s worth the peace of mind to have a shop handle the service.