how to identify a wearing break pad?

[harryhk]

Hey all:

I am wondering if my breaks need to be replaced. Is there anyway to identify wearing break pads which should be replaced?

How about the calipers and rotors? Should I replace them too?

What's the general sign that a break should be replaced?

Thank you very much.

[Moppie]

Hi Harry,

Welcome to AF.


The best way to tell is to take the wheel off and look through the caliper at the pad.
If there is less than about 10mm of material on the pad then it's time to think about replacing them.

However, modern pads come with squealers attached.
These Wear Indicators are small metal strips that rub on the brake disc when the pad is ready to be replaced. They tend to make a pretty awful noise, hence why they get called squealers.



Calipers will only need to be replaced if they are worn out, and in a well serviced and looked after car, they will never wear out.
If the brake fluid has not been changed on a regular basis, or the car has been sitting for a long time then corrosion can build up inside the caliper.
These causes them to stick, leak etc.
You will know something is wrong because the brakes will stop working



Brake discs have minimum width, once work or machined down to this point they need to be replaced.
It's different for every disc, but is usually stamped into the hat.

[harryhk]

Hey Moppie:

Thanks lot for the reply. I attached a pic for the inside break pad viewed from the caliper. I use two arrows pointed to the thickness of the pad. Is that the 10mm you referred to ?

Also I attached a pic of side view my break. There is one piece of metal which is bended my power steering. I am kind of worried about that. I looked in detail, I don't think it actually making contact with the rotor. Does it matters?

Thanks,
Harry.

[harryhk]

pics uploading fail. I will do it some time later.

[Moppie]

Hi Harry,

If you having problems uploading photos try using photobucket.com
They have code for forums you can copy and paste in here.

[harryhk]

I am trying again. Found out the problem. There is a file size limit for each picture. Thank Moppie anyway for the tip.

I attached a pic for the inside break pad viewed from the caliper. I use two arrows pointed to the thickness of the pad. Is that the 10mm you referred to ?

Also I attached a pic of side view my break. There is one piece of metal which is bended my power steering. I am kind of worried about that. I looked in detail, I don't think it actually making contact with the rotor. Does it matters?

Thanks,
Harry.

[Moppie]

Those are some rusty old calipers!
What sort of car is this on?

It's hard to tell in your photo, but yes, that does look like the pad material.
There will be two pads on each side of the disc, and each pad has a metal backing plate that sits in the caliper, and a layer of friction material that sits against the disc.
It's the layer of material against the disc that will wear out.



The bent metal plate is just a dust shield. It's designed to help keep the disc cool, and to keep dust and water away from the brakes.
Being bent like that won't effect the brakes or steering.