Brake fluids are often overlooked, and people are never so keen to know which fluid is used in their cars. With the different categories and the risk involved in mixing the fluids, it is important that you become conversant with this knowledge.
It is possible to use dot 4 brake fluid in lieu of dot 3. This is because they are inherently similar, only that they boil at different temperatures. Both of them are glycol-based, hence compatible. You are therefore using them interchangeably. The dot 4 brake fluid will give you the performance of dot 3, and the converse is true.
This article sheds some light on the different brake fluid categories as well as what the different ratings mean.
Can I Use Dot 4 Instead of Dot 3?
Yes, it is possible to use dot 3 and dot 4 brake fluids interchangeably. The only main dissimilarity between the two is how hot they get before boiling. The properties of dot 3 and dot 4 are almost similar.
While dot 3 has a dry boiling point of 205℃, dot 4 has 230℃. For wet boiling point, dot 3 has 140℃ and dot 4 has 155℃. Their point of compatibility is that both of them are poly-glycol based. However, mixing the brake fluids is not recommended, and if you have to, ensure that you completely drain the brake lines.
What Is the Difference Between Dot 4 and Dot 3?
The concept and operation of brake fluids are not usually well understood. It is used in cars—at least people know that much, but not how or what it does. And trying to decipher the letters and numbers on the fluid is another tricky part.
What many are unaware of is that brake fluids have different ratings which directly affect the performance of their vehicle. But hopefully, this article breaks it down for you.
Understanding the use of the brake fluid, the different ratings, and the differences between the individual brake fluids will help you make the right decision when it comes to maintenance and long-term care of your car’s braking system.
The department of transportation (DOT) classifies brake fluids into four main categories; dot 3, dot 4, dot 5, and dot 5.1. each of the fluids contains different compounds and chemicals.
The main dissimilarity between dot 3 and dot 4 is their boiling points. Dot 3, on the other hand, absorbs less water than its counterpart, and hence, you will be required to have the fluid changed less frequently. With that, you learn that the primary differences between the two lies in water absorption and their ability to handle heat.
When it comes to when you need to change the brake fluid, the owner’s manual should offer instructions on the type and frequency. Also, mixing brake fluids is not recommended as it could cause the brakes to malfunction due to incompatibility.
Can I Mix Dot 3, Dot 4, and Dot 5 Brake Fluids?
Dot 3 and dot 4 brake fluids can be mixed since they are both glycol-based. The dot 5 brake fluid, on the other hand, is silicon-based and thus cannot be used alongside dot 3 and dot 4. Doing so could diminish the braking performance, resulting in malfunctioning or wheel lock-ups when you attempt to brake.
It is vital that car owners understand the different ratings of brake fluids, and that not all of them are compatible with their cars. Unlike dot 3 and dot 4 made of poly-glycol, dot 5 is silicone-based and does not absorb moisture. It also displays a more watery consistency. Mixing the three is not advisable and could have serious consequences.
Is Dot 3 Brake Fluid Better Than Dot 4?
The owners’ manual should give recommendations on the type of brake fluid for your car. Anytime you want to upgrade, ensure that you drain all the old brake fluid from your brake lines to avoid cross-contamination. Also, the general rule of thumb is that the brake fluid with a higher boiling point tends to last longer than others with a lower number.
Dot 4 has a dry boiling point of 230℃ and a wet B.P of 155℃, while dot 3 has 205℃ and 140℃ respectively. Therefore, dot 4 offers better resistance when it comes to extreme heat and delivers reliable stopping power.
The brake fluid may be one of the most overlooked parts of a braking system, but that should not be the case. Without it, the braking performance would be non-existent at best. Also, anytime you wish to change the brake fluid, ensure you get the right one for your vehicle, otherwise, you risk damaging the entire braking system.