How Long Does Unopened Brake Fluid Last?Find Out Now

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Brake fluid is reputed to last for as long as possible without any contamination if it is unopened. It may only begin to develop some denaturation the moment the seal is broken.

This is because by nature,  brake fluid is said to be hygroscopic, which means that it absorbs water or moisture from the atmosphere the moment the seal is broken and it is exposed to the surrounding.

Under ideal conditions, an unopened can of brake fluid last up to about two years or even longer. As a precautionary measure, however, you are advised to use a new bottle of the fluid each time you need it, because of its hygroscopic property.

Table Of Contents

How does brake fluid go bad?

Brake fluid is not known to ordinarily affect or damage most substances such as metals or even some varieties of rubber.

All the same, the moment it is opened and moisture gets absorbed by it from the air, then it becomes quite capable of causing metals to rust or to even affect natural rubber. In essence, brake fluid goes bad mainly when it is contaminated with water.

What happens if brake fluid is not changed?

If you fail to change brake fluid, even after you are certain that it is due for a change for whatever reasons against the recommendations by your vehicle manufacturer, you risk moisture contamination in your brake reservoir where it is stored.

Furthermore, this indifferent or negligent attitude will certainly reduce the braking capabilities of your car greatly, which will lead to very poor braking performance.

Does brake fluid deteriorate over time?

 Reminiscent to what usually happens with natural oil, brake fluid will certainly lose its effectiveness and quality over time, especially when the container is opened.

This is because it will absorb moisture from the atmosphere, which will definitely cause the rusting of metallic substances in the hydraulic system and other problems as well that can make your brake ineffective, because of which you cannot either slow down or stop the vehicle whenever you want. 

How long does DOT 5 brake fluid last?

DOT 5 is one brake fluid that has an impressive shelf life. As long as the seal remains on its container untempered, it can last for much longer than you may never think possible.

This is basically because its silicone doesn’t attract moisture like most other common brake fluids on the market. In any case, you should not keep it unused for more than two years, primarily as a precautionary measure.

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How long can brake fluid be stored?

Brake fluid can be stored for up to about two years without any problems. It should be noted that this is highly advisable despite the claim by some manufacturers that brake fluid does not have an expiration date, as a sort of precautionary measure, just in case, because one can never be too careful, especially with a vehicle’s braking efficiency.

Does brake fluid go bad when stored?

Actually, as long as it remains unopened, you have little or no reason to fret regarding whether it will go bad or not since it is claimed by most of its manufacturers that it does not have an expiry date.

Be that as it may, you are not advised to store it for upwards of two years, at the most, even if its container has not been breached.

If on the other hand the container has been opened, then it becomes quite a risk to store it without expecting issues of contamination due to the ever-presence of atmospheric moisture. So, yes, it can go bad when stored, particularly in instances where it is opened and can as a result attract moisture due to the exposure.

Can I drive with low brake fluid?

Yes, you can, but there are enormous risks associated with doing that. For instance, when your car is low on brake fluid, the effectiveness of your brake is not assured, which means that the car may not either slow down or even stop when you want it to, which is a panacea to a reckless accident capable of affecting you, other road users and all your vehicles. 

Therefore, it is only reasonable to understand that doing so comes with enormous risks, and so it should ( or rather must) be avoided as much as possible. (Read Also:Can You Brake Without A Clutch?)

How do you know when brake fluid is bad?

There are some indications to make you suspect when your brake fluid is bad such as:

*  Your ABS light might come on.

*   You may start having issues with your brake pedal such as when it becomes very hard to press or easily goes to the floor without much effect on your braking effectiveness.

*   You may hear strange noises whenever you are breaking the vehicle.

*   When your brake pads are not working well even though they may be new.

*    When you begin to perceive a strange burning smell.

What are the signs of low brake fluid?

Let us run you through the four cardinal signs that will reliably tell you when your brake fluid is low.

* The ABS becomes activated at odd times even when you are not slowing down or stopping.

* You begin to have issues with your brake pedal.

* Noise coming from your tires.

*  Your brake pads starting to give problems of their own.

Frequently asked questions (FAQ)

What happens if your brake fluid is low?

If your brake fluid is low in the reservoir, it simply means that your vehicle’s braking power is also low too or better still compromised. This inadvertently means that the vehicle may not slow down when you want it to or stop when required, which is obviously a recipe for disaster. (Read Also: Can brake rotors warp from sitting?)

To worsen the situation, this development is also likely to put other brake components at the risk of getting damaged prematurely.

This usually happens because first, the pressure that should be transmitted to the brake pads which is supposed to restrict the car is not sufficient enough to do just that and second, it will also put extra strain on other parts of the braking system thereby overworking them, which may lead to further malfunctions.

Luckily, most modern vehicles are equipped with features that will give you notice early enough to enable you to detect this complaint. Really, the more you know about these basic DIY procedures, the better for everyone; you, other road users, your vehicle, and those of the others too. You never can be too careful. (Read Also: Are Drum Brakes Self Adjusting?)

How long should brake fluid last?

Ideally, brake fluid should last for at least two years or so without any problems, if the can is not opened, even though there may be contrary opinions on the matter.

However, we are all too aware that nothing lasts forever, and for that reason, we cannot easily accept that brake fluid does not expire, a claim its manufacturers have always tried to sell to us.(Read Also: Is it okay to replace only one brake rotor?Find Out)

On the other hand, the brake fluid in your car can last for up to about 30 000 miles or a period of two years while in use the car, which largely depends on your driving and braking patterns.

All in all, if your vehicle sustains heavy use continuously, you could change its brake fluid once after as few as even 15 000 miles. So, that is the long and short of it on how long your brake fluid may last whether it is in storage or while being used. (Read Also:Do Ceramic Brakes Pads Smell?)

Is it okay to use old brake fluid?

It is strongly not advised for you to do that, and with good reasons too. For instance, old brake fluid is most likely contaminated with moisture which can cause rust in the brake system, and as time goes on, the heat that is generated from braking may cause the brake fluid to break down and become more contaminated.

However, if you are certain that the old brake fluid has not undergone any deterioration and is consequently in good condition, then, you might take the risk of using it again.

But then, the question is: how do you become absolutely sure of the status of any old brake fluid, and what criteria do you adopt to ascertain this fact? To be on the safe side, always use new brake fluid and avoid recycling an old one. (Read Also: Does Brake Cleaner Damage Plastic?)

Agreeably, the cost of a can of new brake fluid is much more preferable to that of getting your entire brake system damaged or being involved in unnecessary accidents, or don’t you agree?

Which is better between DOT 3 and DOT 4?

The main difference between these two is that DOT 4 absorbs less water than DOT 3 from the atmosphere over time. This means that you will obviously need to change brake fluid less frequently with DOT 4, which is good for you. In addition, DOT 4 has higher dry and wet boiling points, making it much safer at higher temperatures. In essence, DOT 4 is better.

How much does it cost to get brake fluid changed?

All things put into consideration, a complete brake fluid flush may cost you anything around one hundred dollars, much of which is for the labor involved. Nevertheless, it is worth it, to say the least, because the brake is the most important thing in the car after the engine.

Can I change brake fluid without bleeding the brake?

For one, bleeding is not a compulsory aspect of changing your brake fluid. Essentially, therefore, you can change your brake fluid without necessarily bleeding it. After all, a mere inspection of the fluid does not require bleeding.

Can DOT 5 replace DOT 4?

Commonly, DOT 5 is used as an upgrade or replacement for both the DOT 3 and 4, which must not be mixed with either of them. Notably, DOT 4 is identical to DOT 5 silicone in most aspects, particularly in its boiling point and viscosity, and it is also compatible in the poly-glycol based systems and also the anti-lock brakes (ABS) too.(Read Also: Does Brake Cleaner Kill Wasps?)

What colour should brake fluid be?

Ideally, fresh brake fluid should be as clear as possible with a tint of yellow colouring. Should your brake fluid resemble oil, and as such, it is dark brown or black in colour, then you obviously need a complete brake fluid flush or replacement.

Why does my brake pedal slowly go to the floor?

Your brake pedal may go to the floor when pressed for any of three reasons; faults with the master cylinder, a brake fluid leak and an ABS unit leak.

This pedal malfunction is most noticeable when you have to keep constant pressure on the brake pedal in order to stop the car, in which case you have to either pump it repeatedly or you might find out that it easily sinks to the floor.

How long does unopened brake fluid last – Conclusion

Though the manufacturers claim that brake fluid does not expire, but to be on the safe side, you are advised to store brake fluid for a period not exceeding two years. Where the can of brake fluid is opened, there is the risk of absorbing water from the atmosphere which causes metals to rust.

It is for this reason that you are advised not to store brake fluid for too long especially where the seal is broken. Various brands of these fluids exist, and you are expected to conduct in-depth research on them before you buy according to the instruction manual.

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