Difference Between Dot3 And Dot4 Brake Fluid

Difference Between Dot3 And Dot4 Brake Fluid (3 Best DOT 3 Brake Fluid)

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For you to clearly understand the brake fluid ratings, there is a need to know what brake fluid does.

A vehicle brake fluid is a type of hydraulic fluid that is used to transfer force from a brake pedal.

It can also be used to transfer the brake lever to the brake calliper or wheel cylinder, which will convert it to pressure.

This means that whenever the calliper or wheel cylinder exerts pressure on its brake pad and rotor combination, the friction will slow the vehicle down.

Meaning that brakes convert kinetic energy into heat, which is where brake fluid ratings come in.

 However, the DOT ratings for brake fluid shows their boiling points when they are dry or wet.

Note that brake fluid contains glycol which attracts water. And over time, it’s normal for brake fluid to absorb a particular level of moisture, this shows that brake fluid ratings include both a wet boiling point number along a dry boiling point number.

Are All DOT 3 Brake Fluids Compatible?

If you are asking this question, the answer is no they are not exactly the same chemically.

However, they are only all guaranteed to meet up the DOT specification which is mostly a performance that is measurement/spec.

However, this probably affects some parts of the chemical makeup too.

But note that manufacturers are free to put whatever additives that they want to meet up the DOT spec or exceed it.

The truth is that what brand you choose can matter but you rest assured that if they meet the DOT spec, then they should at least meet the baseline.

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DOT 3 Vs DOT 4 Brake Fluid: Is There a Difference Between DOT 3 And DOT 4 Brake Fluid

Note that these are Glycol-based brake fluids, which are classified by a Department of Transportation (DOT) number: 3, 4, 5.1.

However, these brake fluids don’t have to be classified by chemical composition since there are no specific requirements by the government.

 It simply means that there is no typical brake fluid formula. Meaning that they do need to meet certain requirements by the government.

The DOT3 happens to be the most common type of brake fluid used by daily drivers.

This means that you can expect to find that most cars and trucks use this type. Importantly, it is meant for vehicles that don’t use their braking system aggressively, meaning vehicles that don’t turn the kinetic energy into heat that DOT 3 can’t handle.

While the DOT4 has a higher boiling point and also has found its place in racing vehicles and police cars. The DOT4 has also started to gain popularity recently because of increased usage of ABS and traction control.

  • Their Boiling Points

One of the basic difference between DOT3 and DOT4 is their boiling points. The boiling point is the temperature under which the fluid evaporates and also how they are prone to absorbing water.

However, both the DOT3 and DOT4 are hygroscopic, which means they absorb water.

But due to its lower boiling point, the DOT3 is more prone to water absorption. Also, the DOT3 boils under hard braking much better, which makes the DOT3 less suitable for some activities.

Note that there are two kinds of boiling points, which are dry boiling point and wet boiling point.

However, the dried boiling point can be determined by using the fluid from a brand new container.

While the wet boiling point can be determined by using a fluid that has been contaminated by about 3.7% water.

However, it is possible for moisture to enter the system every time you remove the reservoir cap to add fluid, which will make your fluid’s quality degrade.

This means you should ensure to flush the brake system from time to time just to remove the moisture.

See the table below:

 The Dry Boiling PointThe Wet Boiling Point
The DOT 3205 °C. (401 °F.)140 °C. (284 °F.)
The DOT 4230 °C. (446 °F.)155 °C. (311 °F.)
  • Their Chemical Structures

Just as we said above, there are no specific requirements for their chemical structure as long as they both meet the requirements as seen on the table above.

The DOT3 brake fluid is normally based on diethylene glycol (DEG). Although, it isn’t a requirement but it seems to be the most economical way for producers to meet with the outlined requirements.

Meaning that the brake fluid industry has self-regulated and determined this to be the standard.

The DOT4 happens to consist of glycol and borate ester. This borate is meant for the brake fluid to handle higher temperatures. Just as in the table above, the dry and wet boiling points are greater.

Is Prestone DOT 3 Brake Fluid Good?

Prestone DOT 3 Brake Fluid is a fluid that is a mixture of polyglycol ethers, which prevents the brake-system operation not to cause dangerous vapors.

The fluid is meant for disc and drum brakes as well as ABS systems. The fluid’s wet and dry boiling points exceed the minimum government standards, which provides an extra margin of safety during an extreme braking conditions.

The Prestone DOT 3 brake fluid is one of the most common braking fluids for passenger cars and has a reasonable price tag.

This fluid does more than enough for daily drivers who needs typical braking power without any performance-oriented results.

Using one 32-ounce bottle is indeed enough to completely flush a single vehicle’s braking system.

What Is The Best DOT 3 Brake Fluid Freon?

As you should know, dirty or an-old brake fluid can clog systems from the buildup of rust or deposits which needs constant changing.

However, you should always refer to your car manufacturer’s guidelines whenever it comes to selecting a brake fluid.

And also, brake fluid should be flushed or completely changed according to manufacturer recommendations.

Note that brake fluids should be handled with care, because they are highly corrosive and damaging to paint and other coatings if it is spilled.

And they can also be harmful if swallowed and should avoid contact with the skin or eyes.

So whenever you are having your brake system flushed, ensure the new brake fluid used is stored properly and the old fluid is disposed of safely. So when it comes the what is the best DOT 3 brake fluid Freon, I will say one best you dot 3 brake fluid for freon is Mag1 120 Premium DOT 3 Brake Fluid and that is because it can handle virtually all-weather conditions and also has a higher heat stability rating and has a good fluid consistency for almost every vehicle.

with that said here is a list of my top dot 3 brake fluid for your vehicle in the order of preference.

3 Best DOT 3 Brake Fluid

#1. The Mag1 120 Premium DOT 3 Brake Fluid

The Mag1 120 Premium DOT 3 brake fluid happens to be one of the best DOT 3 brake fluid options out on the market.

This Mag1 120 premium DOT 3 brake fluid has a good fluid consistency that will help your brakes perform at their optimal capacity without any issue of clogging.

This fluid can handle virtually all-weather conditions and also has a higher heat stability rating.

This DOT 3 brake fluid is completely exempted from any corrosion or deterioration because of water retention.

It is a unique fluid because it can be used in regular vehicles and also a high-powered racing vehicle which makes it the ideal brake fluid for everyone.

This great brake fluid can be used for different types of vehicles, but before deciding to use it on your vehicle, reference the content to ensure that you’re making the right decision when it comes to changing your brake fluid. You can get the fluid here on Amazon for a very affordable price.

#3. The Prestone DOT 3 Brake Fluid

The Prestone DOT 3 brake fluid is a mixture of polyglycol ethers, which prevents the brake-system operation not to cause dangerous vapours.

The fluid is meant for disc and drum brakes as well as ABS systems. The fluid’s wet and dry boiling points exceed the minimum government standards, which provides an extra margin of safety during an extreme braking condition.

The Prestone DOT 3 brake fluid is one of the most common braking fluids for passenger cars and has a reasonable price tag.

This fluid does more than enough for daily drivers who needs typical braking power without any performance-oriented results.

Using one 32-ounce bottle is indeed enough to completely flush a single vehicle’s braking system.

However, one of the biggest complaints about this product is, when you order online, it may not have a lid, and the seal might even break during shipping.

Of course, this is problematic since brake fluid absorbs water at a faster rate once the seal is broken. And it can also be contaminated when not sealed properly. You can get it here on Amazon for $3

#3. The Lucas Oil Dot 3 Synthetic Brake Fluid

This fluid in my opinion is one of the best brake fluids on the market as it has an impressive high-quality formulation.

This brake fluid is compatible with every rubber braking system, which is capable of being blended and mixed with other glycol-based braking fluids as well.

The fluid protects and strengthens the brakes so that it last longer and perform better.

One of my choice for the 3 best DOT3 brake fluids, because it meets and exceeds the industry minimum dry boiling point of about 401 degrees Fahrenheit.

Also, it can be used both on disc and drum brakes, and it can even be applied to the clutch.

The fluid helps in protecting your brakes against rust and corrosion, prevention of excessive hardening or softening of the rubber components, and also provides excellent lubricity. You can purchase this fluid here on Amazon for just 8 dollars

What Will Happen If You: Accidentally Put DOT 3 In DOT4

Note that nothing bad will happen to the brake system itself. The DOT 3 and DOT 4 are compatible.

But you should know that the DOT 4 has a higher boiling point than DOT 3. If your car requires it means that its braking system will work hard enough to boil DOT 3 brake fluid. And if that happens, it means you will lose braking power rapidly.

Conclusion

I can honestly tell you that the difference between DOT3 and DOT4 fluids are their boiling points.

These fluids don’t vary much other than the DOT4 containing borate to increase boiling temperatures.

So whenever it comes to changing the brake fluid, the best thing to do is contact the manufacturer’s specifications.  

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