Changing brake pads is hard enough as it is – do I have to bleed brakes when changing pads? Or is there some way that I can do it without doing so? What is the harm if I don’t bleed the brakes? Answers to these questions coming up in the article below.
Changing the brake pads is something that every car owner has dealt with. Whether you are a pro racer or a regular car rider, brake pads on your vehicle will wear out after some time, and you will need to replace them.
Changing the brake pads requires opening the bleeding valve and brake line, resulting in a new set of issues. Opening up the brake line and the bleeding valve results in the air getting inside the brake fluid reservoir. This leads to the formation of air bubbles in the brake fluid.
These air bubbles hamper the baking performance and can result in brake fade, which means the brake pedal will be spongy when you press it, and also, the braking distance increases.
To avoid all these issues, you need to bleed the brakes while changing the brake pads on your vehicle. But is it absolutely necessary? Read on below to find out why is it important to bleed the brakes while changing brake pads.
Do You Need To Bleed Brakes When Changing Pads?
Whether or not you need to bleed brakes when changing pads depends on your method for changing the brake pads. Bleeding the brakes is unnecessary while changing the brake pads unless you expose the brake fluid to air.
If you change the brake pads without opening the brake line or the brake fluid reservoir, then there is no way for air to get inside the reservoir or the brake line, and you don’t need to bleed the brakes.
If other than changing the pads, you have done some additional work on the brakes that require opening up the brake line or the brake fluid reservoir. You would also need to bleed the brake pads.
Bleeding of the brakes while changing brake pads depends on just one condition, whether or not you have opened the brake fluid reservoir or the brake line. Exposure of the brake fluid to air is the main reason behind needing to bleed the brakes.
You might like to read: What Size Wrench For Brake Bleeder Valve?
What are the ways to change your brake pads?
There are two ways to change the brake pads on your vehicle.
Method 2: Without opening the brake fluid reservoir
The first way involves changing the brake pads without having to open up the brake fluid reservoir or the brake line. In this method, you would retract the caliper piston or the brake pads, pushing the brake fluid back into the fluid reservoir.
Since the brake fluid moves toward the master cylinder, it decreases the pressure in the braking system and makes it easy for you or the mechanic to change the brake pads.
In this method, you don’t need to open up the brake line to fit the brake clippers back into place, and thus the brake fluid doesn’t get exposed to the air.
If you have changed the brake pad using this method, then there is no need to bleed the brakes. However, for the proper functioning of brakes, you must bleed the brakes every one or two years.
Method 2: Opening the brake fluid reservoir
The second method to change the brake pads requires opening the brake fluid reservoir or the brake pipes. In such cases, you would need to bleed the brakes as the brake fluid gets exposed to the air.
To understand why you need to bleed the brakes after exposure of the brake fluid to air, first, you need to understand the purpose of brake fluid and how it works.
What does brake fluid do and how does it work?
Brake fluid is responsible for transferring the pressure on the brake pedal while applying brakes. The brake fluid makes the brake pads clamp over the brake rotor.
When you press the pedal, the brake fluid travels to the brake pipe and pushes the brake pad against the rotor on the wheel, which eventually brings the wheel to a complete halt.
You might like to read: 7 Reasons Why The Brake Pedal Goes To Floor When Engine Starts
Why does air get into brake fluid?
Brake fluids tend to absorb moisture when exposed to them. When you open the brake line or the brake fluid reservoir, you expose the brake fluid to air, and chances are the brake fluid will absorb some of the moisture content in the air.
While changing the brake pads, many people open up the brake fluid reservoir as it helps release the pressure on the brake pads, which means the brake pads will be easier to remove.
The brake fluid exposure to air can also happen if you have opened the brake line. The air can travel through the brake line and get into the master cylinder. These scenarios will lead to brake fluid absorbing moisture and air bubble formation inside the brake fluid.
What harm can air bubbles do in your brake fluid reservoir?
Brake fluid tends to absorb moisture, and exposure to the air can form air bubbles. Air bubbles in the brake fluid can cause several issues in the braking system like:
- Brake fade: in this, when you press the brake pedal, it will feel spongy.
- Longer braking distance: when you apply brakes, your vehicle will move a longer distance before coming to a complete stop.
Since the performance of the brakes decreases, it increases the braking distance of your vehicle. Air contains moisture, and as we all know, water has a lower boiling point than the brake fluid.
Mixing moisture into the brake fluid can result in the lowered performance of the brake fluid.
Overheating of the brake fluid will cause the water to evaporate and create air bubbles in the brake fluid reservoir. The air bubbles will not let you apply enough pressure to the brake pads, making your brake pedal feel spongy. You might also face brake fade.
If you face any such issues after you have just replaced the brake pads on your vehicle, you need to bleed the brakes.
To avoid all these issues, bleeding the brake is the appropriate solution. Determining whether or not you need to bleed brakes after changing brake pads depends on how you handled the procedure.
Do You Need To Bleed Brakes When Changing Rotors?
You don’t need to bleed brakes unless you have exposed the brake fluid to air or air bubbles formed during the rotor changing process.
We sometimes open up the brake fluid reservoir or the brake line to release the pressure from the brake rotors and pads to perform the steps of changing the rotors. In such cases, it is essential to bleed the brakes.
You might like to read: Should I Open Brake Fluid Reservoir When Changing Brakes?
Frequently Asked Questions
#1. Do you bleed brakes before or after changing pads?
Whether you need to bleed the brakes before or after changing brake pads will depend on the issue. If the brake pads on your vehicle have worn out and you are going to replace them, it is better to bleed the brakes after changing the brake pads.
If you are experiencing longer braking distances and lower responsiveness of the brakes, air bubbles may have entered the brake line and got into the brake fluid.
In such a case, you can bleed the brakes without waiting to change the brake pads. For your baking system to work correctly, it is essential to bleed them at an interval of one-two years.
#2. What happens if you don’t bleed your brakes?
It is necessary to bleed the brakes on your vehicle at a regular interval. Bleeding the brakes removes the air bubbles from the brake fluid, which helps restore the braking efficiency.
Over time, air bubbles can accumulate in the brake fluid, and it will degrade the performance of the brakes on your vehicle.
If air gets in the brake fluid and you don’t bleed the brakes, then it will result in several issues. The brake response will degrade, resulting in a longer braking distance. The brake pedal will also feel spongy when you press it.
The air doesn’t get out of the braking system on its own, and unless you bleed the brakes, the braking system on your vehicle suffers.
#3. How Do You Change Brakes Without Bleeding?
You can not change the brakes on your vehicle without bleeding. However, if you are only going to change the brake pads, you can do so without bleeding the brake fluid.
If you can change the brake pads without opening up the brake fluid reservoir or the brake lines, then you don’t need to bleed the brakes.
Whether or not you need to bleed the brakes would depend on which process you choose for changing the brake pads.
Some people are worried that if they press the brake pads into place, it may damage the master cylinder on the brakes. That is why they prefer to open up the bleeder valve before changing the brake pads to put the caliper while changing the brake pads.
If you open the bleeder valve, you need to bleed the brakes. On the other hand, in some cars, you can put the caliper back on using a wrench without opening up the bleeder valve and thus don’t need to bleed the brakes.
#4. Is Bleeding The Brakes Necessary?
Yes, bleeding the brakes is necessary for two scenarios. If air bubbles get trapped inside the brake line, it can hamper the brake performance, and that is why it becomes essential to bleed the brakes to remove the air.
Brakes fluids become contaminated and murky over time, and you would need to replace them. In such a case, you need to refill the new brake fluid while bleeding the older one to change the brake fluid.
You might like to read: No Brake Fluid To Rear Brakes When Bleeding: 6 Reasons Why This Happens
A Few Final Words
In simple words, if you did not open the brake fluid reservoir or the brake line while changing the brake pads and have not exposed the brake fluid to air a mixture in any way, then there is no need for you to bleed the brakes.
But if you open the brake fluid reservoir or brake pipe while changing the brake pads, you have exposed the brake fluid to air, and you need to bleed the brakes.
Thank you for reading the article, we hope you got the answer you were looking for. If you still have doubts, reach out to us in the comments section and we will get back to you with answer.
