Does Brake Fluid Go Bad? (Everything to Know)

If you are a vehicle owner, one question that might come to your mind at some point is – Does brake fluid go bad? The truth is, brake fluid does go bad, although this does not occur naturally.

If brake fluid loses its quality, it is better to take out the bad fluid and replace it with a fresh one.

In this article, we will be looking at why brake fluid may go bad and lose its quality, signs of bad brake fluid, when and how to change brake fluid, and the cost of doing so.

Unfortunately, brake fluid is one of the maintenance items most drivers do not take seriously.

Vehicle owners often do not change their brake fluid before it gets bad. Instead, they usually wait until the brakes start to produce a grinding sound, which indicates that the brake is starting to wear out, although this can be easily fixed by changing brake pads and bleeding the brakes after each change.

Also Read: How Much Brake Fluid Do I Need?

Why Does Brake Fluid Go Bad?

Does Brake Fluid Go Bad

brake fluid is hygroscopic (that means it has an affinity for water.) As a result, brake fluid is well known for absorbing water.

Regular brake fluid testing devices available in stores work solely to test and determine if the fluid has other moisture content. However, the shocking fact is that no matter how much effort is put into ensuring the fluid does not absorb any moisture, problems may still arise.

This is because brake fluid can absorb moisture in different ways. For example, it may be while the fluid is being packaged, while the fluid reservoir is being filled, or from the hoses passing brake fluid around.

Symptoms of Bad Brake Fluid

Six symptoms which usually come up when brake fluid is due for a change or top-up will be discussed below.

They are:

1. The Brake Pedal Is Not Responsive.

If pushing down, the brake pedal becomes harder, or the brake pedal must be pumped before the vehicle acceleration reduces, or the brake pedal becomes spongy or too soft.

This could indicate that brake fluid is not circulating in the system as it should. This usually occurs when there is a leak, or the quantity of brake fluid is low. This may also have an overall effect on the performance of the brakes and cause brake failure.

If the brake fluid is leaking, check under the vehicle close to the tires to ascertain if a light yellow or brown substance is leaking beneath the vehicle. When a brake pedal does not respond, or a fluid leakage is spotted, it should be checked without wasting much time.

2. Brake Pads Vibrating

A vibrating brake can also be an indication that the brake pads are worn out or that the quantity of brake fluid in the system is low. If this symptom is noticed, the best thing to do is check the brake pads immediately.

Noisy Brakes

A low quantity of brake fluid in a vehicle can affect the brake pads or the performance of the vehicle’s calipers. When the brake pedal is used, it forces a piston inside the master cylinder, which is usually filled with brake fluid. The cylinder then passes brake fluid around to all the brake calipers on the discs.

The brake caliper has to generate enough pressure that would make the brake pads clamp properly to the tires, reducing a vehicle’s speed until it reaches a complete halt.

A braking system failure is the most likely consequence of little or no brake fluid. If a vehicle’s brakes start making weird noises, checking them becomes necessary.

3. ABS Warning Light

The Anti-lock Braking System dashboard light (ABS) comes on when there is a problem with the ABS. This system prevents the tires from getting locked up while braking so that the wheels maintain traction and do not skid. In addition, having a small amount of brake fluid in a vehicle will activate the ABS automatically, which helps in ensuring the vehicle stops safely.

4. Vehicle Pulling to the Side, Left or Right.

If a vehicle tilts to the right or left side while applying the brakes, this could mean that the brake fluid has been contaminated. This issue should be checked without delay.

Also Read: Low Brake Fluid Symptoms (+ How to Fix)

How Often Should I Change My Brake Fluid?

Does Brake Fluid Go Bad

Many producers who use mineral-based brake fluid usually advise that the brake fluid be flushed out, and a new one be filled in every 36 months. However, for certain vehicles, factory recommendations are unavailable because the fluid will likely stay good for as long as the “lifetime” of the vehicle.

Changing a vehicle’s brake fluid after covering a distance of 30,000 miles or every 24 months is still recommended by Haynes. However, changing fluid annually will be better for vehicles used for towing trailers or for an aggressive driver.

Although the fluid in a vehicle does not look like it has gone bad, changing it very often is necessary. This is because the moisture absorbed by the fluid is usually not visible.

How to Change Your Brake Fluid

Indeed, vehicles differ. Nonetheless, the procedure for changing the fluid in a vehicle stays the same. Before proceeding, one thing to note is that having extra hands to assist with this task will reduce difficulty.

For sure, there are ways in which one man can bleed a vehicle’s brakes. However, having someone around to help press the brake pedal will be more effective.

The preferable way to change brake fluid and bleed the vehicle’s brakes is to have the vehicle jacked up first; afterward, let it rest on a jack stand. Then remove all four tires before starting this task.

1. Drain the Old Fluid

Remove the brake master cylinder’s cap, then take out as much fluid as possible with a turkey baster or something similar. Next, pour the fluid from the vehicle into a container suitable for disposal. Once a good quantity of fluid has been removed, use a clean cloth to clean and remove any particles that may have gotten into the reservoir.

2. Fill It Back Up

Once the first process has been concluded, it is necessary to pour fresh, new fluid into the vehicle’s master cylinder in place of the one removed and fill it up till it reaches the “MAX” point.

Ensure the rightly specified fluid is used, which is usually inscribed on the cap of the master cylinder. Before putting the cover back in place, a few more toppings will be required, so covering the cylinder should not be done in a rush.

3. On to the Calipers/Cylinders

Each drum brake tire cylinder or brake caliper have bleed nipples on its back. Apply some clean brake fluid on all of them to remove the lubricants, then use fluid penetration to make them free.

4. Start With the Furthest

For many vehicles, begin at the most distant angle from the vehicle’s master cylinder. The farthest corner will be the passenger side rear wheel. Connect a short rubber pipe to the bleed nipple.

When this is done, put the opposite end of the pipe in the container where the old brake fluid was drained.

5. Time for a Helper

Get someone to occupy the driver’s seat. Reach out for the first bleed nipple. Prevent the brake lever from being pushed flat to the surface, which can be achieved by using a block to hold the movement.

6. Pump and Hold

The occupant of the driver’s seat should have the brakes pumped three times before holding down the pedal. While the pedal is being held down, open up the bleed nipple to allow the old fluid and air that might have found a way into the lines to flush out quickly.

Close the nipple, then have the pedal pumped and held again. Loosen the nipple and close again. Continue this process until the new fluid starts flowing out with no bubbles.

7. Top-Ups

Always observe the master cylinder’s fluid level because a top-up will be required as progress is made. If the cylinder should go empty, having air pumped into the brake lines and starting all over becomes necessary.

8. Rise and Repeat

Repeat the above procedures for all wheels, ending the task at the closest wheel to the cylinder.

9. One Last Thing

When work has been completed on the last brake caliper, the pedal should feel a little different (i.e., the pedal feels firm.). A firm pedal is a good sign because the brake system is filled with new fluid, and there is no air. After this, check the quantity of fluid available in the cylinder and fill it up if necessary before closing it.

10. Wheels On

As all the vehicle tires are detached, a tire can be switched to another position if the vehicle owner desires. Reattach the wheels, put the vehicle back on the ground, remove the jack, and the vehicle is good to go.

Never forget that serious caution is required for the first couple of miles the car will cover after completing the job on the vehicle’s brakes. The brake fluid level should be checked the next time the fuel tank is filled and, if necessary, fill it up to the MAX level.

Does Brake Fluid Go Bad

How Much Does It Cost to Change Brake Fluid?

The cost of changing the brake fluid of a vehicle will most times depend on the labor fees. Most vehicles use the DOT 4 brake fluid, while others use DOT 3 instead.

Ensure the proper brake fluid is used for a vehicle. The correct brake fluid can be known through the manufacturer’s specifications, which usually state the best brake fluid for the vehicle’s model.

Fortunately, brake fluid does not cost so much. About 32 oz of brake fluid should not cost more than $5.

When changing the brake fluid, it is advisable to have a qualified mechanic handle the task. The labor differs by state. However, an estimated cost of $80 – $130 is usually charged as labor fees.

Also Read: Is Brake Fluid Flammable? (Why You Should Be Careful With Them)

Bleeding or Flushing the Brakes

To “flush brakes” and “bleed brakes” are two different words with different meanings and should not be used interchangeably in the manner many people use them.

To bleed the brakes is to take out air that might have found a way into the braking system. This is often not necessary unless the vehicle is put on the track.

Flushing brakes has never been a bad idea, and it is the best thing to do. To flush brakes, the fluid in the whole system is removed, and a new one is put in its place, which is a very good thing to do if looked at from the perspective of maintaining the vehicle.

Does Brake Fluid Go Bad

Frequently Asked Questions – Does Brake Fluid Go Bad?

How do you know when brake fluid is bad?

Normally, brake fluid has a clear color and is light. If the brake fluid is dirty or transparent, then it is not clean, and there is a need to change it. A point in the fluid vessel should be marked “full line.” If the fluid level goes below the said point, it could indicate that the brake needs to be topped or refilled entirely.

How long does brake fluid last once opened?

Many vehicle manufacturers recommend that once a DOT brake fluid bottle is opened, it should not be used for more than a year. Never forget that the stated year is the maximum limit within which to use the open fluid.

What happens if I use old brake fluid?

Like other fluids, the effectiveness of brake fluid reduces over time. In addition, the fluid’s ability to absorb moisture can lead to corrosion in the hydraulic system and cause other issues that can reduce the overall performance of the brakes and decrease a driver’s ability to halt when the situation warrants such.

Does brake fluid go bad in a sealed container?

Some companies specializing in brake fluid production have given a range in which they believe a sealed engine fluid is safe to use; this range is within 2 – 5 years. Wilwood’s tech line suggests that fluid in a sealed container feels like it is protected till infinity. However, it should not exceed five years, as suggested by some companies.

Is Brown brake fluid bad?

A vehicle’s brake fluid ought to be changed very often. It should not get to a stage where it turns brown or black. Brown or black brake fluid is an indication that the fluid has been seriously contaminated.

Is it really necessary to change the brake fluid?

The brakes could be regarded as among the most important elements of a vehicle’s safety. Nevertheless, many customers wonder If the flushing brake fluid is essential, and a simple answer is YES. A vehicle’s braking system depends on hydraulic fluid to affect the force when the brake pedal is pressed.

Can brake fluid last 10 years?

The DOT suggests changing brake fluid every 24 months because brake fluid extracts water from the air, which reduces the boiling point in the fluid and makes it corrosive. Replacing brake fluid should put the seals in better condition and not the other way round, as the goal is to take out corrosives.

What color is brake fluid when it needs to be replaced?

As stated earlier, fresh brake fluid is usually pure and looks yellowish. However, if a vehicle’s brake fluid is starting to have a black or dark brown color, then the brake fluid needs to be flushed and replaced.

Conclusion – Does Brake Fluid Go Bad?

The brake fluid is one important element that makes a braking system function as it should. Using a good quality fluid improves the system’s condition and works optimally. However, after a while, break fluids of premium quality will go bad because fluid absorbs moisture, which is a contaminant and reduces its effectiveness.

Certain symptoms begin to show when brake fluid goes bad, including noisy brakes, unresponsive brakes, and a vibrating brake.

Due to this, it is only right to change the fluid after some time as this will keep the braking systems in optimum condition and get them to work effectively. Changing bad fluid can be done by the vehicle owner or a mechanic based on preference. However, if available, the fluid should be replaced based on the manufacturer’s specifications.

Scott Greene is a seasoned automotive technician for over 5 years and has been deep into advanced automotive diagnostics for a couple of years. He Loves writing about Automotive Diagnostics and Repair, Trouble codes, Buyer guides for various car parts and accessories, and lots more. 

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