When Does Brake Fluid Go Bad? [Its Shelf Life And Solution]

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Yes, brake fluid goes bad. You should take this piece of information seriously. Interestingly, there’s a scientific explanation for this.

Naturally, brake fluid comes from glycol-ether, a hygroscopic substance. This means the fluid can easily hydrate and absorb moisture from the air.

As the fluid attracts more water from the atmosphere it becomes less effective. When contaminated, brake fluid can become a danger to your car’s braking system.

Brake fluid should prevent the brake components from going bad. Besides, they should reinforce better brake performance.

When the brake fluid gets bad, the brake pads can become spongy; the rotors can warp, and the caliper can wear or rust.

You’ll see out-of-sight brake fluid by its low boiling point and reduced performance. Once exposed to intense pressure, brake fluid will lose its optimal boiling point.

The good news is that there are visible signs you can look out for when the brake fluid is bad!

How To Tell If Your Brake Fluid Is Bad Or Low

Here are a few things that can serve as tips that your brake fluid is no longer suitable for your car:

1. Spongy Brake Pads

The brake pads are the first victims when the brake fluid gets contaminated. Each time you press down on the brake pedal, you’ll notice some spongy, soft, or bouncy feeling.

If your car’s braking system sends back these signs, the victim is always a contaminated brake fluid. At the extreme, you’ll need to press down the pedal to the car floor before the car slows down or stops.

If the brake fluid is low, you can also have this soft, pouncing feeling on the brake pedal. Air will occupy the vacuum that the brake fluid cannot fill. This way, you’ll need to press down on the pedal more than normal to be able to get the needed stopping power.

2. Brakes’ Reduced Performance

The braking system will not perform well if the brake fluid is low or has become contaminated. It doesn’t matter the position of the car. The brakes should be responsive and quick when you press down the pedal. When there’s a delay, it’s likely the brake fluid is bad or contaminated.

The best thing to do is to flush the brake fluid and replace it with another. Reduced braking performance can result from worn brake pads or warped rotors. Damaged brake calipers are also a culprit. You can also check underlying issues for delays and ineffective braking.

3. Scraping Sound From The Brakes

When the brake fluid goes bad, the braking system may begin to produce a strange noise. There are many reasons your braking system can give off an unhealthy sound.

Contaminated brake fluid is a major suspect. You may hear grinding or scraping sounds. You may also hear some burning noise when you hard-brake. This often results from burnt-out brake fluid.

4. ABS Dashboard Light Illuminates

The ABS light on your car’s dashboard will come if there is an issue with the car braking system. Once the anti-lock braking system light comes on, you may notice that the wheel won’t lock when you’re in an emergency.

How Long Can Brake Fluid Last?

The duration of brake fluid depends on a few factors. The storage conditions and operating environment determine how long the fluid will last. The materials of manufacture of the fluid also matter.

On average, brake fluid should last about two years. However, if left open and without a proper storage system, it may not last six months.

The best thing to do is to buy the fluid you would use and exhaust at a time. Storing fluid that is already open might expose it to atmospheric air. Exposed brake fluid will start to deteriorate in value over time.

If your vehicle operates in high humidity areas, you’ll have to change the oil more frequently. Moisture penetrates and absorbs fluid through hoses and seals.

As a normal practice, fluid manufacturers seal every brake fluid bottle. This is to avoid penetration of moisture or exposure to atmospheric air. Any contact with outside air may contaminate and weaken the fluid.

Most brake fluid manufacturers indicate that sealed brake fluid has endless validity use. This may be true to the extent that the fluid isn’t exposed to moisture.

However, when brake fluid has been lying unused on your shelf or in the garage for months, it’ll reduce in quality. Your car won’t get the same level of braking performance. On average, unopened brake fluid should be used before second year after purchase.

On the other hand, if a brake fluid bottle is open, the fluid will be exposed to atmosphere. It doesn’t matter if you’ve used only a little out of the fluid. The fluid starts absorbing moisture the moment you open the bottle. The brake fluid content in an open bottle should be used and exhausted within 12 months.

Else, you can discard it. It is not advisable to pour this brake fluid into your car. Opened fluid may still be near its original boiling point three months into the opening. Anything beyond that, the quality will deteriorate. Low-quality fluid won’t offer quality performance.

What Is Brake Fluid Shelf Life Like?

The shelf life of automotive fluids is the length and amount of time for which they can remain on your shelf. Typically, the length of time brake fluid is usable and fit for your car is 2 years or 30,000 miles.

Once it exceeds the time limit, you may not be able to introduce fluid on your car braking system. Else, you’ll damage it.

The shelf life of brake fluid depends on the amount of moisture it’s exposed due to opened fluid bottle. As we’ve noted, brake fluid can easily attract and absorb moisture from the air.

The more water the fluid absorbs, the less the performance it offers. The boiling point of your brake fluid will decrease when it’s exposed to atmospheric air.

The fluid will weaken and become less effective when used in the car. Then, you’ll feel a failing braking system and low stopping power. Besides, there’ll be a pouncing or soft brake pedal.

What Is Brake Fluid Flushing And Why Do I Need it?

Sometimes, the brake fluid may go bad after some time right inside your car. There’s a chance that atmospheric moisture gets into your car’s braking system. Contaminants, rust, rubber, and other fragments can also start to flake off. They’ll find their way into the fluid.

This debris makes your brake fluid get dirty over time and becomes hazardous to your engine.

What will you do if the fluid gets contaminated after opening, pouring, and using the brake fluid on your car? The only thing is to flush it out.

Brake fluid flushing involves clearing out all the brake fluid in the reservoir. The purpose is to replace it with fresh fluid to offer a breath of fresh air into the car.

Once the brake fluid in your car goes bad, the thing to do is flush the fluid out of the engine. A lot of car owners and drivers wonder if brake fluid flushing is worth the time. You should flush the brake fluid from your car before it destroys the braking system.

Don’t forget, your foot needs minimal effort to stop the hydraulic brake fluid. Brake fluid is essential to reduce the foot pressure exerted to stop or slow down the vehicle.

Reducing the amount of heat generated is a result of brake fluid flushing. Your car’s brake components break down and wear away if there’s insufficient brake fluid. Also, moisture can leave the fluid reservoir, preventing the brake from rusting.

The frequency of brake fluid flushing depends on the quality of the fluid in your car. Your braking and driving patterns can tell how often you should drain the brake fluid.

On average, however, you should do a brake fluid flush every 2 years or 30,000 miles. The cadence of your brake fluid flush is also a function of the make, model, and year of your vehicle. Brake fluid flushing can cost about $100.

So how should you go about braking fluid flushing?

Step-By-Step Guide To Brake Fluid Flushing

There are four important steps and components to drain your car’s brake fluid. A DIY procedure may not be the best idea. To flush your brake fluid, you’ll need to hire an experienced mechanic. This will ensure the proper functionality of the braking system.

  1. Locate brake fluid reservoir.
  2. Place a container under the reservoir.
  3. Hold down the brake pedal while pumping the brakes.
  4. Crack open the valve.
  5. Drain worn, old, and contaminated hydraulic fluid into a container.
  6. Clean out all contaminants, rubber, and other debris.
  7. Pour in new fluid.
  8. Clean up the surroundings of the brake reservoir to complete the process.

Generally, the new hydraulic fluid is yellow; whereas, the old, worn fluid often looks dark. Sometimes, you may need to replace worn and damaged brake components. These include rusted wheel cylinders, worn calipers, or degraded pads or rotors.

As a general rule of thumb, make sure you periodically carry out a braking performance test. This will keep your brakes in order and guarantee quality performance on the car.

Final Thoughts

Bad brake fluid isn’t healthy for your car. A poor braking system won’t guarantee safety, either. As a general rule of thumb, safety is central to everything about the road and car.

If you have to press down on the brake pedal before your car slows, the best thing is to pull over the car. Make a call to a local mechanic for a diagnosis.

When you hear that unopened brake fluid doesn’t expire, you should be wary. It sounds more like a selling strategy. Only use brake fluid that hasn’t been lying in your garage for months. In fact, you should do a brake flush every 30,000 miles.

This will guarantee a healthy, long-lasting braking system. Even though unopened brake fluid may not have expiry date, using it on your car may cause damage. Once brake fluid has absorbed air and moisture, it won’t offer any improved performance.

Choosing between DOT fluid and mineral oil depends on the model, make, and year of your car. Glycol-based DOT hydraulic oil is highly hygroscopic. It mixes easily with atmospheric air and won’t last longer once you open its bottle.

But, mineral oil doesn’t absorb much water from the environment. Once you opened the bottle of the mineral-based fluid, you can store it for a long time.