When your vehicle is in motion, and you stretch your leg on the brake pedal, to apply the brake, there is a little action that occurs here. Once a force comes in contact with the brake pedal, it will cause an action that will stop the vehicle momentarily. In this article, you will learn how to bleed bleed brakes in vehicles.
What does the term brake bleeding mean? It simply refers to a process that allows a small opening of the valve at the wheel cylinder or caliper; this is to result in maximum control of brake fluids to escape the system. Taking a deep thought about bleeding, it could be likened to a graphic term; however, it appropriately describes the release of vital fluids.
Brakes are being bled, to give room to escape of air that will later be trapped, within the system. Technically, air can only penetrate the system, when there is a compromise of the system sealing. A good example is if the flex lines are changed or removed. This is because, there will be fluid vapor when fluid boils, and as a result, there is an efficiency loss in the braking system, if there is air or vapor in the braking system. NOTE: for the sake of simplicity, and easy assimilation, we shall be making use of the term air, to describe air and vapor.
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The air causes inefficiency in the braking system because it can’t be compressed, unlike liquid. Now the question is how does air get into the line? Most of the time, It could be as a result of an upgrade on the system, or service procedure. An example is replacing the stock flex lines of braid lines with stainless steel. Another reason, which is as well mostly common, is when there is a high temperature, which could make the brake fluid boil, thus turning the brake fluid into a vapor.
This would make one complete and reason deeply on the right type of fluid that should be used in the liquid fluid. Judging by theory, simple water can be used, because water can’t be compressed, however, it should be noted that one of the fundamental functions of the braking system, is to generate heat energy from kinetic energy, from a process known as friction. And an indisputable fact of this process is that some of the parts in the braking system are exposed to a very high temperature. We all know that water boils at 212 degrees Celsius, and this heat could be achieved within the braking system, which can easily turn water into vapor, which could lead to inefficiency in the braking system.
An obvious solution to this problem, Is to make use of fluid that boils at high temperature, hence, there will be less vapor in the braking system, but unfortunately, there is no perfect fluid that can work for this. And just as it’s applying to almost everything In this life, the addition of certain characteristics, or similar things to make something work better, always comes with its side effects. Also, when it comes to brake fluid systems, There is a high need to make use of substances that can resist high temperatures, and at the same time, have less impact on other components.
Furthermore, it’s quite possible to reduce a brake fluid sensitivity to temperature by making use of varied ingredients. However, making use of certain fluid that can resist high temperature, can lead to the high cost of brake fluid, and can also have a significant impact, by causing corrosion on other components of the vehicle. The rating of the chemical composition of the fluid is mostly indicated via the following format DOT4, DOT3, DOT5. The DOT rating is always assigned after vigorous government testing. The DOT rating indicates the compound that is present in brake fluid.
An irony about brake fluid is that most of the chemical compound that shows being less sensitive to temperature absorbs the most water.
Now that you have a clear understanding of how the braking system works, let’s dive into, how to bleed brakes. Before then, let’s take a look at procedures that can be used when servicing your car. Please bear in mind that, If you are not replacing your master cylinder, the process is the same, whether your vehicle is equipped with ABS or not.
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The following tools will be needed
- Extra brake fluids
- Box end wrench
- A 12-inch long section of clear plastic tubing
- One assistant of the brake pedal
- Disposable bottle for waste fluid
- One can of waste cleaner
Vehicle premium and support
- Remove all road wheels
- Place the entire vehicle on jack wheel and loosen the lug nuts
- Tighten the nut against the motor surface and install one lug nut backward at each corner,
- Check the level of the brake reservoir, and open the hood.
How to bleed brakes
- Start from the corner of the driver, with an aim, to move toward the driver (left gear, the right gear, left front, right front). The sequence may not have a significant impact on the bleeding of the car; however, it is easy to remember. This will also allow the system to create a bridge between the new fluid and the old fluid.
- Check for the bleeder screw, which is always at the rear of the caliper body (also known as the drum brake cylinder). Make sure the bleeder screw doesn’t get removed as you remove the cap.
- On the bleeder screw, place the box-end wrench over it, because most of the movement depends on it.
- On the nipple of the bleeder screw, place the plastic hose.
- Turn to release the fluid, into the waste line by loosening the bleeder screw. Do not open the screw for more than seconds, because the brake pedal will fall, as the screw is being loosed
- Tighten the bleeder screw as you close it gently. Bear In mind that you do not need to do this with much force.
- Check the fluid within the lines, If there are no air bubbles
- Proceed further with the bleeding process, and repeat the process as many times as possible.
- Systematically, move towards the driver, (left gear, the right gear, left front, right front), as you repeat this process, keep a watchful eye, o the brake fluid of the reservoir
- When you have fully ensured that all the corners have been bled, you can then proceed to spray the bleeder screw, including any of the parts that were dropped or moistened with spilled brake fluids. Make the area clean and dry, so you can easily detect if there is any leakage from any parts of the vehicle.
- Check and test the brake pedal, to ensure it has a firm wheel
- Also, check and inspect the bleeder screw, and also check other fittings, for any signs of leakage.
- Ensure you properly dispose of the used waste fluid, as you usually do, to your motor oil. Take note of this, used brake fluid should never be poured back into the cylinder reservoir.
Vehicle wrap up and road test
- All the four wheels should be reinstalled
- The vehicle should be raised thereby removing the jack stand
- While the car isn’t in motion yet, release and apply the brake pedal as many times as possible, until all clearance is ensured in the system.
- Put the car in motion to ensure everything works perfectly. Drive with caution, do not run too fast, ride slowly and apply the brake steadily to ensure that all the parts of the system are working successfully.
How often do I need to bleed my brakes?
As we round this article up on how to bleed brakes in vehicles, these few rules will help you to determine how often for you to bleed your car brakes.
- If you do not use your vehicles frequently or for interstate traveling, there may be no need for you to bleed your brakes. Some European vehicle organizations do recommend replacement, rather than bleeding the car brakes.
- If you use your car for sports purpose, there is a need to upgrade the brake fluid on annual basis,
- If you attend a driving school, and your car is subjected to a good amount of high-speed braking, you, may choose to skip or bypass this step
- And lastly, all dedicated race cars are advised to be, to be bled after every of their track session.
We do hope you’ve been able to learn a lot from this article.
In summary, we’ve discussed how car brakes work, what makes them work, and what could cause brake failure.
At the start of the article, we enumerate the importance of fluids used in the cylinder, the kind of fluids used, as a vital role to play.
Also, if the air is present within the braking system, it will lead to inefficiency within the braking system.
This article is developed to educate all car owners on how to bleed brakes, the importance of doing it, and all that it entails about car brakes. If this article has been of help to you, kindly share it with others.