Your brakes are arguably the most critical safety equipment on your Toyota. You should have your brake system inspected regularly. A typical brake inspection takes less than 30 minutes and will cover your brake pads, drums or rotors, brake pedal, calipers, pistons, master cylinder, brake lines, and yes, your brake fluid.
With all the different parts that go into your brake system, the brake fluid makes it all work. Too little brake fluid affects your ability to stop. Corroded brake fluid will have the same detrimental effect. Water in your brake fluid has a negative impact as well. So how do you know when it’s time to change your brake fluid? Let’s take a closer look at your brakes and what you need to do to keep them working, including when to change your brake fluid.
How Do Brakes Work?
Image used with permission via toyota.com
Most people’s understanding of how their brakes work consists of pressing the brake pedal to make the car stop. But it’s a much more complex system than that. Your brakes are a series of parts, some mechanical and some hydraulic. When you press the brake pedal, this mechanical process activates the hydraulic element.
Pressing the brake pedal pressurizes the brake fluid, pushing it through the brake lines to the calipers. The calipers squeeze the brake pads onto the rotors or drum sides to slow your vehicle. Your brake pads often wear out first, long before any other part of your brake system. It would be best to have your brake pads inspected once a year or every 2-3 oil changes. Your brake pads will last from 1-3 years, depending on factors like load, driving habits, and temperature.
Your brake fluid remains in a sealed system and theoretically could last many years. However, there are ways your brake fluid can become compromised. Water in your brake lines can do several nasty things. One, it lowers the brake fluid’s boiling point, and in a high-heat application like braking, this can reduce your stopping power. Brake fluid needs to have a high boiling point. Otherwise, it will vaporize. Once vaporized, the vapors are much more compressible than the brake fluid, lessening the hydraulic force you need and ultimately failing to stop your car.
Two, water corrodes metal, causing it to rust. Rust flakes and this flaking debris causes damage to the other parts through which it flows. If the lines feeding your brake calipers become clogged, you lose stopping power. Your brake system’s master cylinder can also clog, or worse, begin to rust. Replacing your brake fluid regularly will prevent these situations from occurring.
What Is Brake Fluid?
Brake fluids today are hydraulic fluids made from a glycol-ether base. Some brake fluids are hygroscopic, which in layman’s terms means they absorb moisture from the air. Glycol-based brake fluid will begin to absorb moisture when exposed to air. Even in a sealed system like your car’s brakes, water penetrates through microscopic pores found in rubber hoses, gaskets, and seals. Areas of excessive rainfall and high humidity often cause moisture problems in brake fluid.
Your brake fluid must maintain a consistent thickness, known as viscosity. The viscosity of your brake fluid must be constant in extreme temperatures. Newer vehicles with anti-lock brakes, stability control, and traction control systems are affected more by reduced viscosity because these systems have more ways for moisture to enter. Brake fluid manufacturers add corrosion inhibitors to counter water’s potential intrusion, but you shouldn’t rely on them.
How Do You Know Your Brake Fluid Need Replacing?
You can’t always tell simply by driving your car and pressing the brakes. However, when you press the brake pedal, you should feel consistent pressure. This pressure should feel the same when you start driving on a cold morning as when you’ve been driving for hours in the high summer heat.
If your brake fluid’s compressibility has increased, you will notice more travel of your brake pedal when stopping. The force required of your caliper pistons and master cylinder to stop your car remains the same, but because the fluid’s compressibility is higher, you need more force which translates to more brake pedal travel. If you experience an increase in brake pedal travel, you should have your brakes inspected immediately. Because your brake system was engineered to be consistent, it’s much easier to detect a change. Your brake pedal should never travel to the floor, or bottom out.
It would be best if you periodically had a qualified technician test your brake fluid for moisture, viscosity, and contaminants. Brake fluid should be light brown, beige, or even clear in some cars. You can open your brake fluid reservoir located on top of your brake system’s master cylinder to get a good look at your brake fluid. A murky brown color indicates old or corroded fluid, and you should have your brake fluid tested as soon as possible.
How Often Should You Change Your Brake Fluid?
No hard rule exists, per se. Most manufacturers recommend replacing your brake fluid between 20,000 and 40,000 miles, or every two years, although a few say never. Check your owner’s manual for your specific vehicle’s requirements.
Testing for moisture and copper content in your brake fluid will give you a more accurate timeline. Copper corrodes faster than other metals. A simple test strip can tell you how much copper your brake fluid contains. When copper levels reach 200 parts-per-million, you should replace your brake fluid. When moisture levels reach 3.5% or higher, you should replace your brake fluid. Our technicians will test for moisture and copper when inspecting your brake system.
At Panama City Toyota, we understand the importance your brake system represents, to you, your family, and those around you. That’s why we include a brake inspection as part of our Express Maintenance service. Our factory-trained technicians are experts at testing and identifying problems with your brake system. You can schedule service online or give us a call. Our pit crew-inspired approach will have you in and out and back to your busy life in no time.
