Wise drivers follow regular maintenance schedules for oil, transmission fluid and air filter changes, but what about brake fluid? After all, it’s critical to a vehicle’s brake performance and safety. Forming good upkeep practices now can help you maintain your vehicle in top shape and save some money. Keep reading to find answers to common questions such as “What color should brake fluid be?” and “How often should I change brake fluid?”.
Look for Light Yellow
Taking care of your vehicle’s braking system includes understanding the role that brake fluid plays. It’s a type of hydraulic fluid that both lubricates your braking assemblies and helps apply the amount of pressure needed to clamp your brake calipers around the rotors and bring your vehicle to a complete stop.
Most brand-new brake fluid is light yellow right out of the bottle, but specific colors can vary by brand and type. Glycol ether-based varieties include DOT types 3, 4 and 5.1 The “DOT” stands for the Department of Transportation, which sets performance and composition requirements for brake fluid in the United States. The three types of fluid vary slightly in color and composition:
- DOT 3: Glycol ether fluid in faint yellow, blue, red or green
- DOT 4: Glycol ether/borate ester mix in clear, yellow or deep red tints
- DOT 5.1: Glycol ether/borate ester mix in yellow, blue or clear
Brake Fluid Categories and Performance
While the three glycol ether-based brake fluid types vary in composition, those differences serve important purposes. Think of it this way: DOT 3 is the basic stuff and gets the job done. DOT 4 is a little more advanced, while DOT 5.1 is considered high-performance brake fluid,
Each of these fluid types has different dry and wet boiling points. The dry boiling point applies to fresh fluid still in its original unopened container. Wet boiling points come into play with fluid that’s absorbed 3.7% water. A quick breakdown of dry and wet boiling points illustrates how the three categories differ:
- DOT 3: 401°F and 284°F
- DOT 4: 446°F and 311°F
- DOT 5.1: 518°F and 374°F
While some vehicles use DOT 3 brake fluid, the majority of those on the road today use DOT 4. Because of temperature and composition differences, brake fluid is downwards compatible. You can use DOT 4 in a vehicle that takes DOT 3, but not the inverse. DOT 5.1’s higher heat tolerances are critical when brake temperatures are hotter than the norm — for example, in towing or racing. These higher tolerances also improve brake performance in situations where you must pump your brakes frequently, as with slick roads or in inclement weather.
Aging Brake Fluid To Be Aware Of
Most drivers should change their brake fluid after two years or near the 30,000-mile mark. Ultimately, the color of your fluid will tell you if it’s time for a change. Regardless of color, its overall clarity changes as it ages due to its exposure to heat and moisture absorption. Dark honey, brown or black fluid, especially if it appears gritty or sludgy, indicates that you’re overdue for a change.
Brake fluid is inexpensive: Most versions cost between $5 and $20. You can easily find 2013 Ford Focus brake fluid plus brake cleaner, safety gloves and any other cleaning supplies you need at your preferred auto parts dealer.
