Difference between Dot 3 Fluid Brake and Dot 4 Fluid Brake

The topic of brake fluid isn’t well-understood. The brake fluids are in charge of transferring braking pressure from the lever to the brake pads. These fluids must be non-compressible to properly transfer force. Some individuals are unaware that brake fluid has various ratings, which might impact how well their car works.

Dot 3 Brake Fluid vs Dot 4 Brake Fluid

The difference between Dot 3 Brake Fluid and Dot 4 Brake Fluid is that DOT 3 brake fluids are non-silicone, petroleum/non-mineral based, completely synthetic brake fluids that may be used in a variety of clutch and braking applications whereas, DOT 4 braking fluids are glycol ether-based, with the addition of borate esters to increase performance.

DOT 3 brake fluid is a glycol-based braking fluid that is used in the majority of modern cars. Continue reading to learn more about this braking fluid, including its applications and limitations. The brake fluid provides the force required to stop the car, whether you have drum brakes or disc brakes.

DOT 4 is a glycol-ether-based braking fluid that also includes borate ester (boron-containing oxyanions), which increases the boiling point of DOT 4. All of this adds up to DOT 4 brake fluids being an excellent performance brake fluid with better dependability. DOT 4 is utilized as an interchangeable brake fluid in place of DOT 3.

Comparison Table between Dot 3 brake Fluid and Dot 4 Brake Fluid

  Parameters of ComparisonDot 3 Brake FluidDot 4 Brake Fluid Brake
DefinitionDOT 3 brake fluids are non-silicone, petroleum/non-mineral based, completely synthetic brake fluids that may be used in a variety of clutch and braking applications.DOT 4 braking fluids are glycol ether-based, with the addition of borate esters to increase performance
Wet boiling point400°F/205°C445°F/230°C
Dry boiling point285°F/140°C310°F/155°C
CompositionGlycol EtherGlycol Ether/Borate Ester
PopularityDot 3 Brake Fluid is the more popular of the two brake fluidsBecause it works with normal traction control and anti-lock braking systems, Dot 4 Brake Fluid is fast gaining popularity

What is Dot 3 Brake Fluid?

DOT 3 brake fluids are non-silicone, petroleum/non-mineral based, completely synthetic brake fluids that may be used in a variety of clutch and braking applications. It’s created by combining glycerin with alcohol. For excellent performance, the braking fluid is based on polyethylene glycol ether technology.

The major benefit of DOT 3 brake fluid is that it has high boiling points, which ensures safe and reliable braking performance at high pressures. This braking fluid is intended to resist both high and low temperatures without boiling or thickening. High temperatures of up to 250° C may be tolerated by DOT 3 brake fluids.

This brake fluid may be used to top up or re-fill clutch and brake systems in heavy-duty trucks, motorbikes, 4WDs, and passenger automobiles. It’s also suitable for agricultural, construction, and mining machinery.

In DOT 3 brake fluid, the rubber component swell is low, resulting in less fluid loss and leakage. It also offers high corrosion resistance, extending the life and dependability of the brake system’s components. It is a popular sort of brake fluid that has been utilized in the braking systems of domestic cars for a long time. DOT 3 braking fluids are glycol-ether-based and include a combination of poly-alkylene glycol and ether. DOT 3 absorbs moisture from the environment in most situations.

What is Dot 4 Brake Fluid?

DOT 4 braking fluids are glycol ether-based with the addition of borate esters to boost performance. The wet and dry boiling points are two things that the borate esters enhance. In comparison to DOT 3, DOT 4 brake fluid has a higher and more stable boiling point. When it starts to absorb water, however, the boiling point drops faster than DOT 3 brake fluid.

According to the established criteria, DOT 4 should have a minimum wet boiling point of 155°C and a minimum dry boiling point of 230°. Only use the DOT 4 braking system if your brake system requires it or if the automobile manufacturer has stated it. This brake fluid is not recommended for use in lower or higher-grade cars.

As the braking fluids continue to absorb water from the air, their boiling point will drop. If you don’t change your braking fluid regularly, the rubber portions in your wheel cylinders and master cylinder will corrode. It is suggested that the DOT 4 braking system be replaced every two years to ensure the brake system’s optimal safety and functionality. When water contaminates the braking system, its lifespan is reduced. This braking fluid is capable of withstanding temperatures of up to 311 degrees Fahrenheit. At 40 degrees Fahrenheit, DOT 4 has a viscosity of 1800.

Main Differences between Dot 3 Brake Fluid and Dot 4 Brake Fluid

  1. DOT 3 brake fluids are non-silicone, petroleum/non-mineral based, completely synthetic brake fluids that may be used in a variety of clutch and braking applications whereas, DOT 4 braking fluids are glycol ether-based, with the addition of borate esters to increase performance
  2. The wet boiling point of Dot 3 Brake fluid is 400°F/205°C while, the wet boiling point of Dot 4 Brake fluid is 445°F/230°C
  3. Dot 3 Brake Fluid is composed of Glycol Ether whereas, Dot 4 Brake Fluid is composed of Glycol Ether/Borate Ester
  4. The dry boiling point of Dot 3 Brake fluid is 285°F/140°C whereas, the dry boiling point of Dot 4 Brake fluid is 310°F/155°C
  5. While Dot 3 Brake Fluid is the more well-known of the two brake fluids, Dot 4 Brake Fluid is quickly gaining popularity due to its compatibility with standard traction control and anti-lock braking systems.

Conclusion

Finally, the capacity to manage heat and water absorption is the difference between DOT 3 and DOT 4 braking fluids. When it’s time to replace your brake fluid, check your owner’s handbook to discover what type of brake fluid your vehicle requires. You should never mix various types of brake fluid since incompatibility might cause your brakes to fail.

It’s no surprise that there are no victors in this Dot 3 Brake Fluid vs. Dot 4 Brake Fluid duel. Even though both fluids perform the same function, they are meant to serve different people. Dot 4 Brake Fluid is for you if you’re the sort whose drifting abilities are legendary on the streets. And if all you want to do is go to work, Dot 3 Brake Fluid should suffice.

References

  1. https://www.autozone.com/diy/brakes/dot-3-vs-dot-4-brake-fluid
  2. https://automotivegearz.com/difference-between-dot-3-and-dot-4-brake-fluid/
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