Brake Fluid Differences

Dot 3 vs Dot 4 Brake Fluid: Differences Explained

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Most car owners do not know that their vehicle uses brake fluid, talk more about knowing that brake fluids have different categories. Though the names sound alike there is much difference. And these differences are what you should know.

Dot 3 is the standard and most common type of brake fluid. You can use Dot 3 brake fluid in vehicles that don’t use their brakes as much. On the other hand, Dot 4 is commonly used in race cars and whatnot. First, you must know the function of brake fluid in a car. Brake fluids are essential in vehicles. They are hydraulic fluids that play a vital role in a braking system. They can be found in the brake lines and its work is putting pressure on the rotors. 

Generally, there are different types of brake fluids, but they’re categorized into silicone-based and glycol-based types. We shall be dealing with the two most types of brake fluids, DOT 4, and DOT 3.

Differences Between DOT 3 & DOT 4 Brake Fluid

Do you know that brake fluids come in different categories? They are DOT 3, 4, 5, and 5.1. The most common and standard type of brake fluid is DOT 3. They are regularly used by drivers and are perfect for vehicles that do not use their brakes at high levels. drivers who do not drive at high speed. On the other hand, DOT 4 brake fluid is suitable for racing cars, because they have a higher boiling point.

If there is no brake fluid, you won’t be able to stop your car. When you hit the brake pedal, the pressure exerted transmits brake fluids into the calipers, pressing the pads into the rotors, causing them to generate friction, and immediately the car stops.

It is very important to know the difference between DOT 3 and DOT 4 brake fluid. You don’t want to make any mistake mixing them up, because they are very much incompatible. The major differences between the two are:

  • Boiling Point Level

Keep in mind that DOT 3 brake fluid has a lower boiling point. This makes it easy to absorb water and very suitable for the wet season. Its low boiling temperature can lead to an inefficient braking system.

While DOT 4 brake fluid has a higher boiling point. And so, its water absorption capacity is low. They are good for your engine and can last for a longer period.

The boiling point is categorized into wet and drypoints. In terms of their boiling point levels, the difference between DOT 3 brake fluid and DOT 4 brake fluid can be highlighted below:

Wet Boiling Point155 oC140 oC
Dry Boiling Point230 oC205 oC
Wet and Dry Boiling Points for DOT 3 and DOT 4
  • Make-up of their Chemical Substances 

The chemical structure of DOT 3 and DOT 4 brake fluid are also different. DOT 4 brake fluid has a higher water-resistant capacity. It is made up of either Glycol Ether or Borate ether. And this makes them best for wet conditions. They can be very active even in hot temperatures. Its content, which is borate and glycol helps prevent your brake system from corrosives.

DOT 3 brake fluid functions properly in both hot and dry conditions. It is made up of Glycol Ether. It is so because of its ether and polyalkene glycol component. They are mostly preferred by regular drivers. This is because they run smoothly and at a normal speed rate.

  • Boiling Capacity

Brake fluid boiling capacity is its ability to effectively function in any condition. Regarding this, DOT 3 brake fluid is better than DOT 4 brake fluid. Reason being that DOT 3 brake fluid is water insensitive and can also perform well when outdoors. While DOT 4 brake fluid doesn’t have the best of performance because of its really low boiling capacity.

How To Get Most Compatible Brake Fluid For Your Car?

Getting a brake fluid is not an issue. Where the issue lies is getting the one that’s most suitable and compatible for your car. We know there’s is DOT 3, 4, 5 and DOT 5.1 brake fluid, but which is best for your engine.

To get a compatible brake fluid for your car, you must know your brake fluid option. For this could help prevent a brake fade. The most suitable fluid should have enough boiling point that will be able to take heat increase. Brake fluid with low boiling point turns quickly to gas, affecting the normal functioning of the braking system.

Additionally, you should get a brake fluid that have a high wet boiling point, this enables them perform well even under hot weather conditions.

Even though DOT 4 brake fluid offers a higher boiling point and level, it is perfectly compatible with DOT 3 brake fluid. DOT 5.1 features a high boiling point, making it one of the most heavy-duty and high-performance brake fluids in the industry. You should keep in mind that DOT 5.1, unlike DOT 5, also works perfectly with DOT 3 and DOT 4 brake fluids. 

How Do Brake Fluids Work?

Brake fluids are an essential part of the car. Without brake fluid, your car’s braking system is in danger. The hydraulic brake system is the most common type of brake that a car uses. It works with a piston which is housed in the brake caliper. 

The piston compresses when you press the brake lever. Some sort of pressure produced as a result of the force coming from the pressing of the pedal. This way, the brake rotors squeeze forcing the pressure on the brake levers. The result is friction which causes the tires to come to a halt. The resultant effect is the conversion of kinetic energy to heat energy which is done with the help of the brake fluid.

Final Thoughts

Having reviewed both brake fluid (DOT 3 & DOT 4), I would strictly recommend DOT 3 brake fluid for all standard drivers with regular driving, they are ideal. While drivers who love it rough and aggressive should go for DOT 4 brake fluid, as this suits their driving method. 

When getting your brake fluid, to be sure, check your manuals. This would help you know which brake fluid is compatible for your vehicle, to avoid mistakes.

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