In this article, we will compare the differences between DOT 3 and DOT 4 brake fluids, mixing procedures, and other factors.<\/p>\n\n\n\n
You may also read Why is my Brake Fluid Green?<\/a><\/p>\n\n\n\n Brake fluid is essential to your car’s braking system because it keeps everything stable. Regarding brake fluid, drivers should understand the difference between DOT 3 and DOT 4. Despite their compatibility, their differences can help you decide the most suitable brake fluid. <\/p>\n\n\n\n One of the most noticeable differences between these fluids is their composition. Thus, the primary constituent of DOT 3 brake fluid is glycol ethers. At the same time, DOT 4 consists of both glycol ethers and borate esters. Moreover, DOT 4 is more effective than DOT 3 because it contains borate esters in addition to esters, whereas DOT 3 only contains esters. <\/p>\n\n\n\n The point at which a liquid transforms into a gas is called its boiling point. Additionally, a liquid’s boiling point may be dry before water absorption and wet after water absorption.<\/p>\n\n\n\n In particular, DOT 4 brake fluid is more resistant to high temperatures than DOT 3 because it has higher boiling points under both dry and wet conditions. Thus, DOT 4 brake fluid with a higher boiling point improves safety and braking efficiency by preventing air bubbles in brake lines.<\/p>\n\n\n\n The boiling point of DOT 4 is higher, which makes it better for situations where the brakes get very hot, like racing, driving aggressively, or in cars with traction control or ABS.<\/p>\n\n\n\n The hygroscopic nature of brake fluids means they also gradually absorb moisture from the surrounding air. Consequently, DOT 3 absorbs about 2% more water yearly than DOT 4 due to its lower wet boiling point. When too much water is in a fluid, its boiling point and frictional properties suffer.<\/p>\n\n\n\n Note: DOT 3 and DOT 4 fluids have different moisture levels, so regular fluid changes are recommended.<\/em><\/strong><\/p>\n\n\n\n It is usually suggested that DOT 3 and DOT 4 be mixed in a car’s brake system after it has been flushed completely. Most experts agree you should follow the manufacturer’s guidelines when mixing brake fluids.<\/p>\n\n\n\n Because DOT 3 is compatible with materials like aluminum, copper, and iron alloys, you should mix DOT 3 and DOT 4 fluids. Conversely, DOT 4 has stronger anticorrosive properties.<\/p>\n\n\n\n DOT 3 is typically the more economical option when comparing the price. But DOT 4 might be a better deal in the long term due to its higher boiling points and long-term system protection, particularly in situations that demand high performance.<\/p>\n\n\n\n People Also Read What Happens If You Overfill Brake Fluid?<\/a><\/p>\n\n\n\n There are a few things to remember when choosing brake fluid for your car’s hydraulic braking system, and doing so will help you apply the brakes more safely and effectively. <\/p>\n\n\n\n If you want to know more about compatibility before mixing brake fluids, look at the owner’s manual or the manufacturer’s instructions. <\/p>\n\n\n\n Eventually, old brake fluid will absorb moisture from the air, significantly lowering its boiling point. Assume the old brake fluid in your system has already caused considerable moisture contamination. In such a scenario, it is preferable to replace the old fluid with a fresh one and flush the entire system instead of adding more. <\/p>\n\n\n\n If you mix DOT 3 and DOT 4 brake fluid, the new fluid will have a boiling point in the middle of the two. So, the boiling point of DOT 4 fluid is significantly higher than that of DOT 3 fluid. <\/p>\n\n\n\n It is, therefore, essential to determine if the mixture’s lowered boiling point satisfies the needs of your braking system. Although the boiling point difference is relatively insignificant, it is necessary for the efficiency of the braking system.<\/p>\n\n\n\n When replacing any old fluid in the calipers, cylinders, or lines, it is necessary to bleed the brakes with new fluid completely. Meanwhile, begin bleeding with the wheel farthest from the master cylinder. <\/p>\n\n\n\n In addition to eliminating fluid pockets and moisture contamination, complete bleeding removes any trapped air bubbles and moisture contamination from the system.<\/p>\n\n\n\n Read this Why is No Brake Fluid Coming Out When Bleeding?<\/a><\/p>\n\n\n\n Before filling the brake fluid reservoir, thoroughly blend the DOT 3 and DOT 4 brake fluids in the prescribed 50\/50 ratio. Putting different amounts of fluids directly into the reservoir can create areas with varying points of boiling, moisture levels, and fluid mixes. <\/p>\n\n\n\n Note: It is recommended that you first mix the brake fluids outside.<\/em><\/strong><\/p>\n\n\n\n Keep an eye on the level and condition of the brake fluid reservoir regularly. As time passes, absorbing moisture will lower the boiling point and make it less valuable. After flushing the system, replace the fluid according to your vehicle’s repair manual. Furthermore, keep old, contaminated fluid out of the system.<\/p>\n\n\n\nDOT 3 vs DOT 4 Brake Fluid Comparison<\/strong><\/h2>\n\n\n\n
![\"DOT](\"https:\/\/carfluidpro.com\/wp-content\/uploads\/Dot3-vs-Dot4.png\")
<\/figure>\n\n\n\nComposition<\/strong><\/h3>\n\n\n\n
Boiling Points<\/strong><\/h3>\n\n\n\n
DOT 3 vs DOT 4 – Reliability<\/strong><\/h3>\n\n\n\n
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Water Absorption<\/strong><\/h3>\n\n\n\n
Compatibility<\/strong><\/h3>\n\n\n\n
Price <\/strong><\/h3>\n\n\n\n
DOT 3 and DOT 4 Brake Fluid Mixing Factors<\/strong><\/h2>\n\n\n\n
![\"DOT](\"https:\/\/carfluidpro.com\/wp-content\/uploads\/Dot3-vs-Dot4-mixing.png\")
<\/figure>\n\n\n\nManufacturer’s Guidelines<\/strong><\/h3>\n\n\n\n
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Moisture Check<\/strong><\/h3>\n\n\n\n
Understanding Boiling Points<\/strong><\/h3>\n\n\n\n
Full Bleeding<\/strong><\/h3>\n\n\n\n
Normal Mixing Ratio<\/strong><\/h3>\n\n\n\n
Brake Fluid Monitoring<\/strong><\/h3>\n\n\n\n
Mixing DOT 3 and DOT 4 Brake Fluid: A Step-by-Step Guide<\/strong><\/h2>\n\n\n\n