There are a lot of car maintenance tips that your mechanic might never tell you, especially when it comes to brake fluid change.
Did you know that you can change your brake fluid yourself? Or that not all brake fluids are the same and using the wrong brake fluid can damage your braking system?
Your car’s braking system is one of the most delicate and critical safety components of your car, and your brake fluid plays a key role in its functionality. Designed into your brake system, the brake fluid ensures smooth and responsive braking, sustains friction and transfers the required pressure needed to stop a car in motion.
However, over time, your brake fluid starts absorbing moisture and contaminants. If left unchecked, this will reduce your braking efficiency, cause brake failure and drastically impact your safety.
In this guide, we’ll cover everything you need to know about brake fluid changes, signs of bad brake fluid, and how to properly change your brake fluid.
What Is Brake Fluid and Why Is It Important?
Brake fluid is a hydraulic fluid that transfers pressure from the brake pedal to the braking system. The mechanism of a brake fluid is simple.
When you press your legs on the brake pedals, the fluid converts the applied force into pressure, allowing your vehicle to slow down or stop. In fact, without brake fluids your car’s brakes won’t work.
However, the importance of brake fluids goes beyond transferring pressure but also helps in lubricating the metal components of the brake system like the calipers, ABS control valves, cylinders, etc. It protects these components from corrosion, absorbs moisture, thereby guaranteeing optimal brake performance.
Common Brake Fluid Types
There are different types of brake fluid available. These brake fluid types vary in different ways from their performance ratings, boiling points, characteristics, and composition.
Understanding the brake fluid suitable for your vehicle will help you make the right maintenance choices.
Here is a comparison table of the different brake fluid types and the types of vehicles that they are suitable for:
| Brake Fluid Type | Boiling Point | Suitable For |
|---|---|---|
| DOT 3 | Lower (Glycol-based) | Standard vehicles |
| DOT 4 | Higher (Glycol-based) | Performance & heavy-duty cars |
| DOT 5 | Silicone-based | Classic & military vehicles, and cars built for cold climates. |
| DOT 5.1 | High-performance | ABS and racing cars |
Pro Tip: Never mix DOT 3 or DOT 4 with DOT 5, as they have different chemical compositions.
Is a Brake Fluid Change Really Necessary?
Yes. It is necessary to change your brake fluid. Brake fluids deteriorate over time; hence you must change these fluids as soon as the need arises.
Brake fluids are hygroscopic, meaning that they attract and absorb moisture from the air. The more water is trapped in the brake fluid, the more its boiling point is reduced and its performance impacted.
When the boiling point of your braking fluid is reduced as a result of contamination either by dirt or water, your brakes will start heating up and the fluid will start boiling.
\It can overheat and the liquids turn into gas, leading to brake failure. When this happens, you don’t have brakes anymore and this can lead to a catastrophic accident.
The strange part is, after the accident, when the cause is being investigated, it will be hard to connect brake failure to the issue because the boiled fluid must have cooled down and converted back to liquid.
Effects of Old vs. Fresh Brake Fluid
| Brake Fluid Condition | Effects on Braking Performance |
|---|---|
| Fresh Brake Fluid | Smooth braking, quick response, and optimal stopping power |
| Old/Contaminated Brake Fluid | Spongy brake pedal, longer stopping distances, risk of brake failure |
Factors That Affect Brake Fluid Life
Here are some factors that affect brake fluid life:
Moisture Absorption
The most common factor that affects brake fluid life is its hygroscopic nature. Brake fluid naturally absorbs moisture from the atmosphere and this affects its lifespan.
When the brake fluid absorbs so much moisture, there’ll be corrosion, lower boiling points, and reduction in braking performance.
Driving Conditions
Reckless driving, frequent stop-and-go at traffic and even off-road rides can wear out brake fluids faster. The more the brake fluid is subjected to excessive heat, the more it will break down. Driving in cold weather can also lead to faster brake fluid degradation.
Climate
Extreme weather conditions can wear out brake fluids. Driving in excessive hot or cold weather exposes the brake fluid to humidity and extreme heat. This can quickly degrade the brake fluid.
Vehicle Type
The type of vehicle that you are driving can also determine how fast the brake fluids will deteriorate. If you are driving performance cars or heavy-duty vehicles, you need to change your brake fluids more frequently than someone driving regular cars.
What are signs that you need to change your brake fluid?
Here are some signs that you should look out for, to help you decide when to change your brake fluid:
- Spongy or unresponsive brakes
- Dark, dirty, or cloudy brake fluid
- Burning smell when braking
- Brake warning (ABS) light on dashboard
- Longer stopping distances
Step-by-Step Guide to Changing Brake Fluid
Tools and Materials You’ll Need:
· Correct brake fluid type (check your owner’s manual)
- Wrenches
- Bleeder valve tubing
- Brake bleeder kit or assistant (Hose, Turkey Baster and Zip tie)
- Catch container for old fluid
- Safety gloves and goggles (If necessary)
Check Your Brake Fluid
The first step to changing your brake fluid is locating the brake fluid reservoir. This is usually on top of the master cylinder inside the car’s engine bay. When you find it, inspect the fluid color. If it’s dark brown or black instead of light amber, it’s time to change the fluid.
Use the Turkey Baster to suck out the dirty fluid in the reservoir
Before you start draining the fluid, you need to use a turkey baster to suck out as much dirty fluid as you can, from the reservoir. Get your catch container into the engine bay, beside the master cylinder and carefully suck and empty in the container.
Be careful so you don’t spill brake fluid on the engine parts as brake fluids are corrosive and can affect the metals when spilled. When you are done sucking out as much dirty fluid as you can, pour in new fluids, but in small quantities so you can drain out the old brake fluids remaining.
Drain the Old Brake Fluid
Use a wrench to loosen the bleeder valve on each brake caliper, so you can drain the remaining brake fluids from each of the valves. The valve is located close to the brake line behind the brake caliper.
Attach a clear tube to the valve, leading into the catch container. When you want to drain the valves, start from the valves farthest from the master cylinder. This means you should drain from the passenger side rear to the driver’s side rear, the passenger side front, and then the driver’s side front.
Pump the brake pedal a few times until old fluid drains out
When a hose is attached to the valve, slightly open the valve with a wrench, then march the brake pedal a few times so the old fluid comes out. Repeat process for all the valves in all tire positions.
When you are done, ensure the pedal is firm to ensure there is no air in the system.
Refill with New Brake Fluid
Pour fresh DOT-approved brake fluid into the reservoir and fill up till the required max level.
PROS AND CONS OF CHANGING YOUR BRAKE FLUID YOURSELF
How much does a brake fluid change cost?
The cost of brake fluid change varies depending on if you are doing it yourself or hiring a professional to help you. Other factors that can determine brake fluid change price include the type of brake fluid used and the labor cost of the mechanic. However, you should expect to spend between $50 and $150 to change your brake fluid.
How often should brake fluid be changed?
You should change your brake fluid at least after every two years or 20,000 miles. However, you don’t need to wait till it gets to 2 years or 20,000 miles, especially if you notice signs that the brake fluid needs to be changed.
FAQs
What are two important things to never do with brake fluid?
Two important things that you should never do with brake fluid include: not pouring brake fluid on the ground or through pipes, and ensuring that you don’t spill the brake fluids on your car components, wires, or metal parts as it may damage them.
What happens if brake fluid is not changed?
If brake fluid is not changed after a long period, it will degrade, which will potentially lead to reduced stopping power, damage of brake components, and brake failure.
FINAL THOUGHTS
You must realize how important your braking system is, and how well you manage it, will determine your safety. You should regularly check to confirm the color of the fluid, look out for signs, and ensure that you maintain good driving habits to avoid degrading the fluid faster.
Always use the right type of brake fluid for your car and do not forget that proper brake fluid maintenance isn’t just to sustain the longevity of your car, but to ensure your safety and that of other road users.
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