Brake Servicing, Brake Pads and Rotor Machining


As I am try to keep things fairly simple, and just start with the most commonly fixed parts on the car, I decided to talk brakes.

Now, most would agree that having brakes that work well is fairly important for a car. But when your mechanic rings you and says that your brakes need replacing, and gives you a few options - which is the right one for you? To help you make this decision, I would like to break it down a little so you can make an informed decision.

Brake Master Cylinder

There are a few different components that make up the braking system. One part that rarely needs work on, so I won't go into too much detail about (although it is still an important component), is the brake master cylinder.

The brake master cylinder holds the brake fluid, that allows you, when you depress the brake pedal, to send fluid down the lines to the brake calipers, (will talk to you about these in a bit), that makes the brake pads grip the rotors to stop the car.

Complicated - I know, but when the brake master cylinder goes, it needs to be replaced. It is located in the engine bay, so I won't have a photo of it for you. This also houses the brake fluid you may be asked to pay for to get changed (always a good idea!!).

Brake Pads

Ok, so let's get into the bits and pieces you will hear about most. The first is brake pads. Now, I would be surprised if you hadn’t heard of these. Without good brake pads your car will not stop. Brake pads wear down over time due to friction when gripping the rotors to stop. In the picture below on the left is a worn brake pad and on the right is a new one - big difference!

worn brake pad and a new brake pad

Brake Pad Cradle

The next part is the brake pad cradle. This holds the brake pads in place on the rotor to stop them from moving around.

brake pad cradle holds the brake pads in place on the rotor

Brake Rotor/Brake Disc

The next component that you might hear about is the brake rotor or disc. Both terms are correct (so not really sure why they have 2 names for it). These are what the pads grip to, to stop the car. These also wear down over time and they have a legal thickness to them. So what that means, is when they get too thin they have to be replaced.

You may also get offered a machining of the rotors to prevent a brake shudder. This will always cost you more than just replacing the brake pads, but it is important for a couple of reasons. The first is to prevent a brake shudder. Now, I don’t know about any of you, but if you have had a brake shudder before you will never want another one again.

Interestingly, they are not actually dangerous - Michael left me driving my old Toyota Prado (big 4WD) around with very young kids, with the worst brake shudder that came through my steering wheel and made me think my wheels were going to fall off! If the rotors are thick enough then the rotors can be machined, or smoothed off, to prevent the shudder or any squeaks. Smooth rotors also prevent premature brake pad wear.

So, in short, if it is recommended to machine the rotors or replace them, it really should be done. Below is a picture of an old rotor that has a bit of rust on it and should be machined or replaced when the brakes pads need replacing.

old rotor that has a bit of rust on it and should be machined or replaced

Brake Calipers

The last item I will talk about, but also generally doesn’t need a great deal of work on, are the brake calipers. People who do a lot of off-roading will have the most issues with these. These are part of the hydraulics that make the brake pads grip the rotors. It sits over the brake pads and cradle.

brake calipers are part of the hydraulics that make the brake pads grip the rotors

Car Brake Components Reassembled

So, when it is all done and put back together it will look something like this.

rotors have been replaced, not machined

The rotors in this picture have actually been replaced, not machined as they were too thin to be done.

So, hopefully I haven’t confused you and have made understanding the braking system a little easier, so when you are called, and generally put on the spot, you can decide how far you want to go with the options they give you.

Please if you have anything you would like me to write a blog on, send me message and I will make it happen!

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