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How do I know which brake fluid to use DOT 3 or DOT 4?


Regular motorists often use DOT 3 brake fluid, which is the most common variety. It is appropriate for cars that do not brake suddenly or harshly. Due to its greater boiling point, DOT 4 is more frequently used in racing cars and police cars. Although DOT 4 and DOT 3 may coexist, the reverse is not true.


The variable boiling performance you'll get from mixing DOT 3 and DOT 4 shouldn't be harmful. Since these braking fluids are compatible with one another, combining them is not an issue. There is not much of a distinction between the two. However, I would suggest using one professionally.



There must be adequate brake fluid in every car. You'll need brake fluid whether you're operating a little car, a big commercial truck, or a motorcycle.

Glycol ether-based DOT 4 brake fluids also include borate esters to increase performance. You could, among other things, have superior wet and dry boiling points with the borate esters.


All DOT 4 fluids are synthetic brake fluids with the same chemical make-up. Since the wet and dry boiling temperatures of all DOT 4 braking fluids are the same, you can use any one of them according to your preferences. They are a mixture of glycol and borate ester.



There are numerous number subcategories for glycol-based braking fluids: 3, 4, 5, and 5.1. Although there isn't a single universal brake fluid recipe, they still need to adhere to the government's set of criteria. The criteria for a variety of various categories, such as pH levels, chemical stability, water intolerance, and oxidation resistance, must be met by the standards.


Even at high braking pressures, DOT 3 brake fluid guarantees a dependable and secure braking experience. You won't need to be concerned about this brake fluid boiling or thickening at high or low temperatures.


When DOT 3 brake fluid is required by the vehicle's manufacturer, use this brake fluid. The fluid is inherently hygroscopic and collects water from the atmosphere, decreasing the product's efficacy. Once the brake fluid bottle is opened, make sure to tightly reseal the cap to keep water from contaminating it.


This brake fluid may be used to top out the clutch and braking systems of heavy-duty commercial vehicles, motorcycles, 4WDs, and passenger automobiles. This fluid can be used in mining, agriculture, and construction machinery.


Can I substitute DOT 4 with DOT 3?


dot 3 and 4 brake fluid

If you wish to move up from DOT 3, you can utilize DOT 4. Due to its high boiling point, DOT 4 is perfect for use in police cars, racing automobiles, and motorcyclists that participate in rigorous breaking. Additionally, it works with vehicles that have anti-lock brakes. If the automaker recommends using DOT 4 brake fluid, it is wise to do so.


How do I choose the right brake fluid?


In the owner's handbook, you can always find information about the brake fluid that is suggested for your particular car. The brake fluid reservoir lid, which is located someplace close to the brake booster, may also occasionally have this information printed on it. Anyhow, moving from DOT3 to DOT4 fluid is a good idea because it will raise the boiling point of the fluid and make the braking system more resilient to heavy loads. However, it is not advised to reverse the process.

Compressibility is not intended for brake fluid. Therefore, applying pressure to the brake pedal will cause the air bubbles in any braking fluid to condense, which will cause the car to

have a harder time slowing down.


This is dependent on the braking fluids you have combined. Nothing radically different will occur in the case of DOT3 and DOT4, other from differences in boiling point. Since DOT3 has a lower boiling point than DOT4, adding it to a DOT4-based braking system might cause the brakes to fade more quickly while stopping large loads. And when things are going south, you don't want it. Additionally, both of these braking fluids are glycol-based and cannot be mixed with the silicone-based, more recent DOT5 version.


Are DOT 5 brake fluids recommended?


DOT 5 brake fluids have a few disadvantages as well. When warmed, it swells considerably, and the additives can evaporate at room temperature, enhancing how spongy it feels. This fluid cannot be used in systems that have previously utilized glycol-based fluids unless you flash it and replace the seal. In addition, because silicone fluids are more viscous, they are incompatible with anti-lock brakes. Silicone braking fluids begin to compress at temperatures between 300- and 350-degrees Fahrenheit, as opposed to glycol fluids, which begin to compress as they approach their boiling points.


Standing on the brakes while rounding turns might generate enough heat to induce brake fade if you enjoy driving your car around winding country roads for some light treatment. A little bit of overzealousness might result in you cutting straight through a turn and entering the woods.

The brake fluid may heat up quickly when you drive your car aggressively up hills or when towing a trailer and brake often. The last thing you want to happen up a hill with a trailer is to lose the ability to brake your car if it heats up too much and begins to boil. Therefore, it is crucial to have a boiling point that is as high as feasible.


What occurs if the incorrect DOT brake fluid is used?



This is dependent on the braking fluids you have combined. Nothing radically different will occur in the case of DOT3 and DOT4, other from differences in boiling point. Since DOT3 has a lower boiling point than DOT4, adding it to a DOT4-based braking system might cause the brakes to fade more quickly while stopping large loads. And when things are going south, you don't want it. Additionally, both of these braking fluids are glycol-based and cannot be mixed with the silicone-based, more recent DOT5 version.

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