Understanding The Costs Associated with Changing Your Brake Fluid

Changing your vehicle’s brake fluid is easier than you may think. The key is choosing the proper fluid type for your vehicle. This guide explains your brake fluid options plus how to save money on supplies.

Breaking It Down

Brake fluid comes in four types: DOT 3, DOT 4, DOT 5 and DOT 5.1. As you’ve probably surmised, the “DOT” in these fluid grades refers to the Department of Transportation. That’s because the DOT sets standards for brake fluid composition and performance on vehicles in the United States. Each grade has a different chemical base:

  • DOT 3: Glycol ether
  • DOT 4: Glycol ether, borate ester
  • DOT 5: Silicone
  • DOT 5.1: Glycol ether, borate ester

 Brake Fluid Chemical Bases

You’ll note that DOT 5.1, DOT 4 and DOT 3 have glycol ether bases. They’re downward compatible: You can use DOT 5.1 in a vehicle that normally takes DOT 4, and DOT 3 vehicles can use DOT 4. However, you cannot do the reverse. DOT 5.1 and DOT have higher boiling points than DOT 3, which means they can withstand higher temperatures.

DOT 5 is silicone based and will not work in vehicles that use glycol ether fluids. The reverse is also true. Mixing silicone and glycol ether fluids will result in gelling and lead to poor brake performance. Eventually, this causes complete failure of your braking system. 

Boiling Points and Brake Performance

Why are boiling points important with brake fluid? Let’s consider the amount of heat that’s generated when you press the brake pedal. Things can get pretty hot down there even during regular commuter driving — temperatures between 250° and 350° Fahrenheit are common. If you ride or pump the brakes, this generates even more heat. Towing and racing put the most strain on brakes, which can make them much hotter. 

Most vehicles take one of the three glycol ether brake fluid types. The reason they’re downward compatible is their boiling points: The higher the boiling point, the higher the braking temperatures they can withstand. DOT 4 and DOT 5.1 fluids are less likely to vaporize during high-friction and -temperature applications than DOT 3. Each brake fluid type has different dry and wet boiling points:

  • DOT 3: 401°F and 284°F
  • DOT 4: 446°F and 311°F 
  • DOT 5.1: 518°F and 374°F 

The dry point refers to fluid in its original state in an unopened container. Wet boiling points affect brake fluid that’s absorbed 3.7% water by volume, which is usually the case when the fluid’s been in your vehicle for about two years. That’s why most drivers should change their brake fluid every two to three years.

Brake Fluid Costs

Wondering about the cost of changing your brake fluid? Fortunately, brake fluid itself is inexpensive. Depending on the brand and size you buy, you could pay anywhere between $5 and $20. Professional brake flushes and fluid changes average at around $100, of which about $80 is labor costs.

Read Also : Choosing a Bracelet for a Man

Saving with Autozone

If you’re comfortable performing vehicle maintenance yourself, you can change your own brake fluid. Anyone with intermediate skill level should be able to perform this task in under an hour. You just need to ensure that you’ve got the proper tools and supplies — and your brake fluid, of course. AutoZone is a great place to find what you need: You can save money shopping either online or at AutoZone locations across the country. 

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