Mercedes W221 start button light switch and parking brake e1537620896635

How to Change Brake Pads With an Electric Parking Brake

In Brakes by Magnus Sellén3 Comments

Mercedes W221 start button light switch and parking brake

Modern cars are getting a lot more complicated and nowadays, you can’t even replace your brake pads on your own vehicle without a computer.

This is at least what we are hearing from our customers. But how is this the case? Has it really got to the point where you need a computer to replace your rear brake pads on your new Audi or Volkswagen car?

In this article, you will find all the answers you need about electric brake pads on the most common cars on the market.

How do I know if I need a computer to replace my rear brake pads?

First, we have to figure out if you really need a computer to release your brake pads before replacement. There are some different ways to figure this out. The first thing is, of course, to call your authorized dealer or check your repair manual to find out how to replace your brake pads. You can often find the repair manual online by searching for your car model and repair/service manual.

The other thing is to check it manually by jacking up your car safely and taking a look underneath the car at the brake callipers. There are two different types of brake calipers when you have an electric handbrake.

1. Separate electric motor on each calliper

electric brake caliper

The first type has a separate electric motor on each brake calliper. This is the type of calliper that we need to use a diagnostic tool to be able to push in the pistons. These types of brake callipers, you will often find in Audi, BMW, Volkswagen and other German cars. You can also often find these in American cars. You can see this type of brake calliper on the image.

If you realise that you have an electric motor on your callipers, with a separate wire to it, you can go through to the next step in this article about how to replace your brake pads with an electric parking brake.

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2. One electric motor with wires

The other variant is that the car uses an electric motor underneath the car, which pulls two steel wires, just like a normal handbrake. You can identify this by following the brake wires; however, if you have an electric parking brake and you can see the wires on the brake calipers, you most likely have this variant.

This variant is most often found on Japanese cars like Toyota, Nissan, Kia, Hyundai and Honda. Just remember that on some cars with these brake calipers, the left side piston can be left threaded, and you have to turn it counter-clockwise to push in the piston. Test it carefully and see if the pistons are getting pushed in or coming out when turning.

With these kinds of brake calipers, you do not have to use a diagnostic scanner to replace the brake pads, you can push in the pistons with a tool like this on Amazon on the link down below, but always make sure by checking your repair manual before replacement.

OrionMotorTech Brake Piston Caliper Compressor Tool Setir?t=reviewjam 20&l=am2&o=1&a=B01FW3U26G

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How to replace brake pads with an electric parking brake

So, if you have identified your brake calipers and realised that you have a model with an electric motor directly on the pistons, you can continue to read here.

Because the piston inside the calliper has a threaded rod inside, you have to twist it back and then you have to use a diagnostic tool to push in the pistons and replace your brake pads.

You have probably also heard that you can push it back with one power and one ground cable. That’s true, but not something I can recommend because you can easily damage things and yourself. You will also probably get a warning light on the dashboard after you have replaced it.

Go through these steps and the replacement of the brake pads will get a lot easier. You need some tools to do this properly. If you don’t want to buy them, you could always borrow them from a workshop or a friend if you ask nicely.

1. Connect a car battery charger

You should always connect a battery charger when you are doing this job. Without it, you can get low battery voltage and destroy electrical parts of the electric parking brake.
If you don’t have one at home, I can recommend this one for a universal use: NOCO Genius G3500 6V/12V 3.5A UltraSafe Smart Battery Charger.

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2. Connect a diagnostic tool

maxicom mx808 OBD2 scannerBefore you start taking anything apart, I recommend that you start with the electric parking brake tool. If you have already started the job, the best thing to do is to put everything together again to make sure that your pistons aren’t pushed out from the calipers when using the tool.

If you don’t have a suitable OBD tool for this job, you need one that works with your vehicle and can read the electric parking brake control unit. The cheaper OBD2 scanners can often only read the engine control unit.

Always read the item description so you know that it works with your vehicle. It has to be able to read the parking brake control unit. You can find a suitable OBD2 scanner here on our other article: Best OBD2 Scanner.

If you have an OBD2 scanner, plug it in and follow the instructions of how to start the electric motors to push in the pistons. You will hear when the tool screws back the piston rods. The warning lights will start flashing. At this point, you can now shut off the ignition to make sure you don’t damage anything while you are doing the job.

3. Replace brake pads and push back pistons

Now when you release the piston rods inside the calliper, you can change the brake pads and push back the calliper with a suitable tool (a big plier etc.) or with a tool used for normal rear brake pads replacements like this one on Amazon.

When you put everything back, you can go to the next step.

4. Press the foot brake pedal

Warning: Always do this after a brake pad replacement immediately!! If not, it can result in serious injuries or damage to your car. If you fial to do this, you will drive out from your garage and the brake pedal will go down to the floor when you are trying to brake without any braking force at all.

Push the foot brake pedal a lot of times until you feel that the piston has reached the bottom until it gets stiff.

Be sure to not press the brake pedal to the bottom because you can damage the seals inside the brake master cylinder.

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5. Connect the diagnostic tool again

Now you can connect the diagnostic tool again and use the function, “After brake pad replacement”.

You will hear when the brake calipers have reached the pads.

6. Set a basic Setting

After you have done all the work, you have to set a basic setting with the diagnostic tool. It will push the piston rods forward and backwards a couple of times to learn the default values and store it in the parking brake control module.

7. Test the electric parking brake function

You can now test the electric parking brake function a couple of times to see that it’s working properly. Take the car out for a long drive to see that everything is okay.
Check that the rear brakes don’t get very hot, thst there are no strange sounds and of course the brakes should work properly! Take a test drive and make sure that your ABS-Light or other warning lights are not ON!

You are done!

You see, it isn’t that hard at all if you have the right tools (like every job). So, the electric brake caliper thing was maybe not as bad as you expected. The pros of brakes are probably fewer than with the old style ones, but at least you don’t have to push the handbrake with force everytime, and there is most likely not the same chance of forgetting to release the parking brake with your trip.

I hope you liked this guide and if you have any questions or something you want us to add or change, you can comment in the comments below and I will try to answer all your questions as fast as possible.

Hello I'm Magnus, the owner and the writer of this website. I have been working with cars since I was 16 and I'm specialized with in-depth Automotive diagnostics. Also been driving drifting for the last 6 years. I'm here to give you answers to all your automotive questions and I hope that you enjoy our content.

3 thoughts on “ How to Change Brake Pads With an Electric Parking Brake ”

Comments
  1. I was under the impression that all of the electronic park brake system have pistons that push straight back (after the motor is released) whether euro or asian cars

    1. If that happened Larry, then how would the motor refit… as the piston will be extended to the same position as it was in when the worn pads were in situ. Clearly, the motor mechanism needs winding back. On German cars like Audi and BMW, this can be done with the required OBD2 diagnostic tool.

  2. The certified mechanic was changing my chrysler 200 brakes and rotors when the electronic brake, with separate motors on each rear caliper, engaged while the caliper was off the rotor. The piston came all the way out and fluid leaked everywhere. Now he is scared to complete the job. Do I need new caliper?s

  3. Due to a very high demand and high ammount of comments, you have to wait for some time for your car questions to get answered. If you want to get fast answers from a certified master technician you can ask your questions here:
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