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All Articles on Brakes

When Should You Change Your Brake Fluid?

Brake fluid is almost a forgotten fluid for many vehicle drivers, even those who regularly check their engine oil and tire pressure. While brake fluid is often neglected, as the lifeblood of your braking system; it has one of the biggest jobs of all.

Brake fluid transmits the pressure from your foot on the brake pedal to the master cylinder and on to the calipers that clamp the brake pads and stop your wheels (if you have disc brakes). In essence, without brake fluid, there are no brakes.

Here are some guidelines and reasons for monitoring this all-important yet easy-to-forget-about fluid.

When should you change your brake fluid?

Other fluids have clear-cut rules and expectations about when to change or flush, but with brake fluid replacement, there is no standard between manufacturers. However, since brake fluids share common properties, there are generally accepted principles for brake fluid replacement in the automotive industry:

  • Replace brake fluid anytime the tests show the fluid is a fail or near-fail
  • Replace brake fluid at a service interval of two years or 40,000 kilometres to help prevent brake failure
  • Replace the brake fluid any time major brake replacement is being performed to ensure the brake system continues to work as designed.

Here at Kal Tire, we’ll check your brake fluid for moisture as team members move through our True Service Inspection Sheet on any service. We can identify brake fluid which would no longer withstand the heat generating in braking. We recommended changing your brake fluid every 40,000 kilometres or every two years as a preventative measure.

Kal Tire feels the best time to replace brake fluid is during a major brake replacement. When your vehicle was new, all the brake components were new. When we are replacing a component as important as your brakes, we think it’s important to get all the related components back to new vehicle performance as much as possible.

What happens when you forget about your brake fluid?

Brake fluid is unique in several ways. First, it runs in a closed system, which is why it’s sometimes forgotten about and yet all the more important to keep fresh.

Second, brake fluid is hydroscopic, meaning it absorbs moisture and expands. Because of its nature, brake fluid will pull water through hoses and rubber connections. If the master cylinder reservoir is off, the fluid can pull water right out of the air.

Unfortunately, even four or five drops of water are enough to be detrimental to your braking system and your safety. Why? Water in the brake fluid decreases its boiling point, allowing the fluid to boil and the brake pedal to fall to the floor.

What would you notice if your brake fluid was dangerously low or contaminated with water?

  • Low pedal
  • Spongy or dropping pedal, especially if you’re stepping on it several times as you drive down a hill
  • High, firm pedal if you’ve waited until it’s really bad and some components have rusted and don’t move

Unlike with other fluids, you may not be able to tell when your brake fluid has deteriorated simply by looking at it. Like all other fluids, it’s best to replace brake fluid before you notice any difference in your braking system.

When you think your brake fluid is ready for replacement, make sure you don’t use anything other than brake fluid. Better yet, see the experts at a Kal Tire location near you for a complete inspection of all your fluids and filters as well as your tires, brakes and undercarriage.