Brake fluid is a substance that aids in activating the brakes of your vehicle, making it a crucial component of a hydraulic braking system. It can be found within the brake lines and works by bringing the force from the brake pedal to the calipers and brake rotors, which then causes the wheels to gradually halt.
To ensure that your brake fluid is working at its best, be mindful of its boiling point. Once it boils, the brake fluid turns into gas bubbles that compromises its ability to transmit force, thus causing problems to the hydraulic system. One way of preventing this is to refrain from putting your vehicle in situations that will require prolonged braking. This should keep your brake fluid in the right temperature and your hydraulic system in tip-top shape. In case you’re not sure of the boiling point, consult with your car’s owner manual.
What are the types of brake fluid?
There are two main types of brake fluid: glycol-based and silicone-based. These are then further classified by their boiling temperatures. Brake fluids may come with DOT 3, DOT 4, DOT 5, or DOT 5.1 label. Glycol-based brake fluids are used in cars installed with Anti-lock Braking System (ABS). Silicone-based brake fluids, on the other hand, are used in non-ABS vehicles.
Note that once your vehicle has run on glycol-based fluid, it’s not advisable that you replace it with a silicone-based one, as the leftover glycol can mess with the composition of the silicone-based fluid. This can cause braking problems, which can compromise you and your passengers’ safety.
DOT 3 brake fluid
The DOT 3 brake fluid is a glycol-based substance that is known for its versatility and ability to tolerate temperatures reaching up to 250-degrees Celsius. It is stable enough to maintain its consistency in high and low temperatures. Not to mention, it prevents rust and corrosion from forming in your brake system. It is compatible with a wide range of vehicles such as 4WD, motorcycles, passenger cars, and agricultural equipment.
To maintain the fluid’s integrity, make sure to put the cap back on the container after use. Also, avoid getting your skin or any part of the body of your vehicle in contact with the fluid to avoid irritation or staining. Just use the brake fluid where it is supposed to. There’s no science to back up so-called hacks such as using brake fluid on headlights to keep them clean, which means attempting them may just cause more harm than good.
DOT 4 brake fluid
Just like DOT 3, DOT 4 is also glycol-based. However, it has certain additives that allow it to operate at a higher minimum boiling point. This is usually used for motorsport vehicles and needs to be maintained more frequently than DOT 3.
DOT 5 brake fluid
Unlike DOT 3 and DOT 4, this type of brake fluid does not attract water, which is good for protecting the brake components from rust and corrosion. However, the DOT 5 brake fluid comes at a premium price so use only as required by your vehicle’s make or model.
DOT 5.1 brake fluid
DOT 5.1 has the same chemical composition of the first two classifications of brake fluid. On top of those, it shares the same minimum wet and dry boiling points with DOT 5. Certain vehicles require the features that only the DOT 5.1 brake fluid has.
Signs that you need to change your brake fluid
To check if you need to change your brake fluid, keep an eye out for any of the symptoms outlined below:
Illuminated ABS light
An illuminated Anti-lock Braking System (ABS) light can mean two things. Either your ABS is not connected properly or you need to check on your brake fluid.
Issues with the brake pedal
If your brake pedal won’t work as smoothly as it used to, then it may be a sign that your vehicle needs a fresh change of brake fluid. Either that or you need to top up the amount of brake fluid that is currently in your car.
If you start hearing a noise coming either from the surrounding components of your brakes or the pads themselves, chances are the existing brake fluid may be too dirty to allow for silent operation.
While this doesn’t necessarily mean you need that you need to change or refill your brake fuel, a burning odor inside your car can mean that something is wrong with your brake system. Extreme heat in the engine causes your brake fluid to reach its boiling point so better head to your nearest mechanic to have your car checked.
How often to change brake fluid
How often you should schedule changing your brake fluid depends on the make, model, and year of your vehicle. It’s best to check with your automaker or the owner’s manual just to be sure. In general, any time between one to two years should be fine for maintenance. Despite your brake fluid lasting long in controlled environments, moisture and contaminants can enter the components of your braking system. This can compromise the integrity of your brake fluid and cause problems in running your brake system.
How much does brake fluid flush cost?
Getting your brake fluid flush along with replacing the fluid can cost about $100. This can vary depending on the type of fluid you need and the professional fee of the mechanic who will do it for you. Ideally, brake flushing should be done every 30,000 miles to ensure that everything is clean inside prior to filling your system with new fluid.
In case you feel that your brake fluid is not dirty yet and you just want no air bubbles along the brake lines, then you may opt to just bleed your brakes. Brake bleeding gets the job done without shelling out too much money on brake flushing. But then again, it’s best to consult an expert when making this sort of decision as they are better informed on what to do. The health of your brakes is very important in road safety so it pays to be diligent about it.
Choosing the Right Brake Fluid
The braking system is regarded as the primary safety feature of any automobile. The reasoning behind that needs no explanation, of course. You know exactly how important it is. That knowledge should push you to put extra effort in maintaining your braking system.
Maintaining your braking system involves changing brake fluid every 30,000 miles. Yes, you may have sufficient brake fluid in there, but it may already be old and worn-out. Old and worn-out brake fluid is practically useless-flush it out and replace it with a fresh supply.
Changing brake fluid isn't that hard to do. But before you get to that, make sure that you've got the right replacement brake fluid.
Types of Brake Fluid
As you most probably know, there are several types of brake fluid-DOT 3, DOT 4, DOT 5.1, and the silicon-based DOT 5. The types indicate ratings (which are based on their boiling points) given by the Department of Transportation (DOT). Below is a short description of each type.
DOT 3 ? This is the most basic brake fluid. It meets the minimum boiling point set by the DOT.
DOT 4 ? This type of brake fluid has a boiling point that's considerably higher than DOT 3. A higher boiling point means greater protection for your braking system. It's the brake fluid of choice of many automotive owners.
DOT 5.1 - This type of brake fluid has a boiling point that's only slightly higher than DOT 4 but comes at a significantly higher price. Unless you drive your car on race tracks, it's best to settle with either DOT 3 or DOT 4.
DOT 5 ? This type of brake fluid is specifically designed for old cars that aren't equipped with an ABS system.
Which Type Should You Get?
So, what type of brake fluid should you choose? If you only use your vehicle for normal everyday driving (going from home to work, etc.), then you should go with either DOT 3 or DOT 4. As noted above, DOT 5.1 and DOT 5 are for specialized applications. They're also more expensive than the other two types. But to be sure what kind of brake fluid your vehicle requires, check your car manual.
Once you know what type of fluid you need, decide how much you're going to buy. You can opt for the economical 1/4-L bottle (which is available for as low as $5) if that's all you require but choosing the big 5-L bottle will save you more money in the long run.
How to Flush Old Brake Fluid
Apart from driving well and observing traffic rules, you'd also have to take care of your vehicle properly in order to maximize your safety on the road. And since the braking system is your car's primary safety feature, paying extra attention to it is advised. One aspect of the braking system that requires maintenance every now and then is the supply of brake fluid. It's recommended that you change it every 30,000 miles. Why, you ask? It's because even fluids get old and worn-out. And once they get to that point, they'll no longer be effective.
Simply topping off your old brake fluid supply isn't ideal. You must flush out your old supply in order to make the most out of your new brake fluid. Flushing your old brake fluid isn't that difficult, we'll guide you every step of the way on how to do it.
Difficulty level: Moderate
- Tire iron
- Jack stands
- Clear Plastic Tube
- Small block of wood
Step 1: Park your car on a level surface. Chock your front wheels and activate the parking brake to be safe.
Step 2: Pop the hood and find the brake fluid reservoir. Drain all the fluid that's inside it.
Step 3: Once the reservoir has been drained, fill it with a fresh supply of brake fluid.
Step 4: Take your tire iron and loosen the lug nuts on the wheel that's on the passenger rear side. Don't remove the lug nuts yet though.
Step 5: To be safe, lift each corner of your vehicle using a jack. Place jack stands underneath each area afterwards.
Step 6:> Now, remove the lug nuts that you loosened earlier. Naturally, pull the wheel off afterwards and set it aside.
Step 7: Grab a clear plastic tube and go under the area where you pulled the wheel. Find the brake bleeder valve and insert the tube over it. Place the other end of the tube inside a container or a pan.
Step 8: Position a small block of wood under the brake pedal. Ask the assistance of a friend or a family member and have him step on the brake pedal several times before telling him to hold it down. The small block of wood is there to prevent the pedal from being over-pushed.
Step 9: Make sure that the tube and the pan/container that you prepared earlier are set properly. Now, open the brake bleeder valve. Old brake fluid and air bubbles will start flowing out of it via the tube you inserted and into the pan/container. Tighten the valve afterwards.
Step 10: Repeat step 9 until there are no more air bubbles and old brake fluid coming out. New brake fluid (the fresh batch that you put earlier) should be coming out by then. Refill the brake fluid cylinder if necessary as you shouldn't allow it to be depleted.
Step 11: Repeat steps 7-10 for the other wheels. Secure all of your wheels afterwards and lower your car back to the ground.
Now, take your car out on the road and test your brake. Pat yourself on the back for a job well done!