One of the things we often take for granted is brake fluid. No one sits around the dinner table discussing its benefits or merits, and why should they? But think about it for a moment and you might wonder how it allows even the frailest of drivers to stop a two-ton vehicle with one foot. What does brake fluid do that makes this possible?
What is brake fluid, and what does brake fluid do?
Brake fluid is a hydraulic fluid that moves components within the braking system. When you press down on the brake pedal, the compression builds pressure in the braking system, which forces fluid down to your brakes. That pressure squeezes the brake pads onto the brake rotor to slow you down. The brake fluid must operate perfectly at high pressures and temperatures because of braking’s high-stress, high-friction nature. Because of its harsh working environment and essential use, you should regularly check the brake fluid to try and ensure proper braking performance in every condition.
What are the types of brake fluid?
There are four types of brake fluid: DOT 3, DOT 4, DOT 5 and DOT 5.11. The “DOT” stands for “Department of Transportation,” The three letters mean that the DOT has set, tested, and provided safety regulations for the brake fluid’s performance.
None of the four fluid types are the same. There are differences in composition between what you would use in your perfectly normal SUV and what would be used in a 500-horsepower sports truck. For example, cars with anti-lock braking systems (ABS) use DOT 4 and 5 brake fluids due to extra additives that improve their ability to take the heat. A higher DOT rating doesn’t necessarily mean it’s better for your car. Instead, use the type specified by your owner’s manual.
Signs you need to change your brake fluid
Owner’s manuals and online information from the manufacturer will give you guidance on recommended maintenance. However, you can change brake fluid anytime you choose. Even driving in stop-and-go commuter traffic can be classified as harder than regular use. If you’re looking for signs, here are a few that will let you know that your brake fluid may need to be changed.
- You have to press the pedal down farther than usual to get the car to stop. This can also happen if your front brake pads’ friction material has worn down to the point they need replacing. Either way, it’s time to see what’s wrong.
- You have to press the brake pedal down more than once. The need to pump the brakes lets you know there isn’t enough brake fluid in the system to stop at a safe distance. The need to pump your brake pedal more than once slows down your reaction time and can cause an accident. You should carefully drive to a location that can inspect your braking system.
- The brake warning light on your dashboard lights up. If this happens, you should carefully drive your car to the closest automotive professional and have it checked out as soon as possible.
What if you don’t ever change your brake fluid?
It’s not unusual to go years without changing brake fluid. You may think that everything is OK because you don’t feel like there’s a problem, but that doesn’t mean there aren’t issues boiling, sometimes literally, that could cause an accident. Here are some things that happen when a brake fluid change is put off.
Moisture contamination
Generally, you should never open your brake fluid reservoir cap unless you’re changing the fluid. Glycol-based brake fluid is hygroscopic, meaning it’ll absorb any moisture that’s present. The brake fluid system’s sealed environment protects it against moisture and air.
But even in this system, age will cause seals to slowly deteriorate, letting air and moisture contamination creep in. Moisture can lower the boiling temperature and turn into a gas which causes vapor pockets to form. This will cause your pedal to feel spongy, and your braking will lose its effectiveness.
Debris build-up
As your brake fluid ages, it will also be contaminated with debris. Seals and hoses naturally corrode in the fluid over time as they age. Particles from metal components can also corrode as brake fluid ages and takes in moisture. Keep the brake fluid reservoir cap closed so that things won’t make their way into the system.
Although you can find the bulk of the debris suspended inside your brake fluid reservoir, some of it is bound to find its way into the ABS unit. The debris can build up inside the tiny passageways of the hydraulic unit, eventually plugging them closed. Of course, this could render your ABS non-functional and have dangerous implications for your car’s braking performance.
Poor braking performance
When you don’t change your brake fluid, your car’s braking capabilities can degrade significantly. In most cases, you can tell simply by pressing the brake pedal if it feels incredibly spongy, then there’s a good chance your brake fluid has nearly given up. You might notice that it takes more effort and time to bring your vehicle to a stop. In some cases, you may even have to pump your brakes to build up enough pressure for a safe stop.
Nelson Xavier Ssenyange
Team Leader
Germax Autos, Spares & Garage Ltd
Lukade Road, Naalya
0779250886/0752088734