In order to bleed your vehicle’s brakes, you first need to know some very important things. First of all, you must know what brakes are and how they function. Because only then will you be able to understand why brake bleeding is important and what brake bleeding is and most importantly, how it is done.
We have divided the articles into subtopics so that it is easier for you to understand each and every one of those points we mentioned above;
What is Brake bleeding?
Brake bleeding, as we know, is a process that is performed on hydraulic brakes where the brake lines that includes the pipes and hoses through which the brake fluid flows are purged to remove any of the air bubbles that have been formed within them.
This method for the bleeding of the brakes is also called brake flushing or brake purging.
It is a necessary maintenance procedure and ought to be done regularly depending upon your car’s usage, performance, and model, etc.
Why is Bleeding of the Brakes so important?
It is extremely important, and we will tell you why. The brake fluid is supposed to be an incompressible fluid. However, with the formation of air bubbles within it makes it a little compressible. This can result in a great reduction into the hydraulic pressure that the brakes apply on the tires to stop them and hence the brakes don’t apply properly.
Every time the brake fluid reservoir is opened, a little bit of air makes it’s way inside and gets into the hydraulic system. This air can cause great damage.
The car’s brake system entirely depends on the fact that how readily the brake fluid flows through it and anything that disturbs it causes a hindrance and must be removed. Every time we press the brake pedal a signal is conveyed to the cylinder to compress the caliper’s inner piston so that in turn squeezes the rotor which again, in turn, reduces the speed of the car eventually bringing it to a halt. Nonhydraulic brakes even though operate a little differently, still depend a great deal on the steady flow of the brake fluids.
Method: Apparatus and procedure:
In order to properly bleed your brake’s, you are going to need the following items:
1. A wrench or a combination wrench that fits the bleeder nozzle on your car or vehicle.
The first component is a combination wrench. Even though the same procedure can be performed with a closed-end hand wrench, but there are special wrenches for bleeding of the brakes, and it is better that you purchase them.
These wrenches easily get into tight spots and are helpful because they are manufactured in a way so that they don’t slip off while you are working on the bleeder. They may not be a necessity, but if you do the work on a regular basis, then they are definitely worth the $5 that they cost on an average.
There are a number of different types of wrenches that are available in the market at different affordable costs. However, their cost may increase or decrease, depending upon the type of wrench that fits your car. On average they will cost you around $5-7 and are totally worth investing in if you want to bleed your brakes on your own or own an auto-mobile shop or a garage.
2. A new can of proper brake fluids so that you can replace the old one.
The second component is a good quality brake fluid. Theoretically speaking even water could be used as brake fluid, but it is not, and there are certain reasons why. Let us tell you what those reasons are.
The work of a braking system is to convert kinetic energy to friction energy in order to slow down or stop the car. Now during this process, some essential parts of the braking system get hot and reach a temperature as high as 1200 degree Fahrenheit. This heat is then transferred to the brake fluid, and its temperature might reach approximately 300 degrees Fahrenheit, which is higher than the temperature at which water boils, that is at only 212 degrees Fahrenheit. Therefore, you can see that it is impractical to use
Water as a brake fluid because it will convert to steam at high temperatures and then the fluid would become compressible. Another issue with water is that it may freeze to the ice during winters. Therefore the best solution is to use a fluid that is less prone to temperatures and doesn’t easily boil or freeze.
The variety of brake fluids are rated in terms of DOT3, DOT4, and DOT5. These ratings don’t mention their boiling points just their composition whether or not it is suitable for the braking system depending upon their boiling and freezing points. But there is a slight downside to these fluids, and that is over time they absorb water and their boiling points reduce. This can cause trouble.
- A glass jar to put the brake fluid in so you can fill it in there later.
- And a person to help you with the pressing of the brake pads while you fill the brake fluid as it is a two men job.
How to bleed a brake step by step:
- Find a little nozzle located right behind your car’s brakes. This nozzle is called brake bleeder nozzle.
- Loosen the screws using the wrench:
- Place a hose at the end of the screw and the other end in the jar:
- Have the person with you to pump the brake pedal:
- Once they have done it a certain number of times, open the bleeder screw:
- Don’t release the brake pedal before you have tightened the screw again:
- Keep repeating this procedure until no air comes out of the screw:
- Now add more brake fluid to the master cylinder until it reaches the level of the marked line:
- Repeat the same process with all the brakes:
- It is good to give your car a little drive around the block after you are done with the bleeding of the brakes:
If you are having trouble trying to reach the bleeder screws, then you can try jacking up the vehicle. It gives you a clear view and makes your job easier. Once you are done with this, reach for the nozzle behind the brakes.
Now using your brake bleeder wrench loosen the screw. Don’t use too much strength while you are at it because that might damage the screw all together, and things might get messy. To loosen it up a bit, you can use a Penetrant like WD-40. Once the screw has been loosened, you need to tighten it again.
Now it is time to change that brake fluid. Use the glass jar you brought along and fill it with brake fluid. Place one end of the screw at the nozzle and its other end in the jar. Some of the fluid might drip so place the jar right below the hose to prevent it from falling to the ground.
You cannot loosen the screw and release the brakes. Because then air will be sucked into it. Therefore, have a friend sit inside and tell them when to press the brakes and when to release them
If there is any air trapped inside the fluid, it will come out, and you can easily see it as air bubbles. They are easy to spot in the hose suction method, but you can identify them otherwise as well.
This is very important because if you release the pedals without tightening the screws first, it will suck air again and the air will then get infiltrated into the fluid.
It’s possible that some of the air was still not removed in the first go, so it’s better to repeat the process several times to be sure.
Bleeding the master cylinder is the same as bleeding the brakes. You can bleed it at the point where the brake lines are attached to the cylinder or at the master cylinder’s bleeder nozzle if you can find any.
Now you can repeat the exact same procedure with all other brakes.
Giving your car a test run is a good option. You can check for the change in how the brake pedal presses. It should not feel spongy anymore. If you still feel some problem, you can fill the master cylinder again and make sure that the fluid is up to mark. Or you can bleed the brakes one more time.
We hope that after reading our step by step detailed guide on how to bleed the brakes, you have learned the process. It is a simple procedure but tries to be careful while you are doing it. You have also learned about how important brake bleeding is and how often it needs to be done. We hope this article helped you with what you were looking for.