Let me start by saying that I'm not a car expert (but with all the troubleshooting on my Audi, I might eventually become one). Last spring I started hearing a grinding noise from my front-right wheel. So when I was getting the oil changed I asked the guy at Valvoline if I need to do do anything about the brakes. He said that my front pads are getting thin, but I wouldn't need to replace them for a while. A month later I started noticing rusty dust on the side of my car right behind the front right wheel. I took it to a real mechanic and he said the pads were completely worn and I'd need to replace the front rotors as well. I got the rotors and since I didn't know any better, generic pads.

Now I started hearing the same grinding noise. At first I thought something was wrong with my front pads again, so I inspected my brakes. The front pads both look fine (both are about 1/2 inch thick). The pads on the rear wheels, however, are a little less than 1/4 inch now. So I'm guessing it's the rear wheel that's making the grinding sound this time and not the front. However, doing a search on the forums, it seems like grinding means that the rotors are getting damaged and I should have heard whistling-like brake noises before-hand, which never occured. Will I have to replace rear rotors as well if I order the pads this week and get them replaced when they arrive (1-2 weeks from now)? Why wouldn't my brakes make other noises prior to grinding? Also, based on a couple threads from my search, I was thinking of going with PBR Ceramic pads (http://www.ecstuning.com/Audi-B6_A4-...g/Pads/ES2193/) instead of the OEM, are those decent or should I go with something else?

 

There are only a few times when rotor replacement is warranted, although because they are a high dollar item, many will try to tell you they need to be replaced when you replace the pads. Never replace your rotors unless one of these conditions exist:

1. You visually verify that they are cracked or warped.
2. You visually verify that they have been 'turned' on a rotor lathe to a point where it would be no longer safely legal to put them on a car. The mechanic can give you the exact parameters for that rotor, and show you the measurements on the lathe that would put it too thin for application specs.
3. There are still obvious deep grooves or pitting after they've been turned.

I can't think of any other reason to replace a rotor, but there won't be many other reasons, that's for sure.

As for the squeaking; yes, some pads do have built-in tabs that will 'chirp' or 'click' when the pad is within thickness of being replaced. a lot of times, people won't notice the chirping because their stereo is on, and by the time they hear the squeal, the metal plate attached to the pad is digging grooves into the rotor. That can get so bad that it digs in even when the brakes are not depressed, but by then you are usually hearing an obvious metal on metal grind, even when you are going slow.

Other reasons for squeaking are pads not bedded and being glazed over. Brake dust and pads not fitting tightly into the calipers are two other causes.

Different pads have different compositions and will perform different and last different lengths of time. Do the research and you should be fine. Just always err on the side of safety.

And although very few mechanics and service shops will do it for you, it is important that you bed the breaks when you change them or have them changed. This will prevent glazing. At its most basic, bedding is stopping smoothly but quickly from 30 miles per hour about 10 to 20 times, giving the brakes over 30 seconds between each stop to cool down. You also want to ensure you are nice to your brakes for at least the first 200 miles.

Lastly, make sure that your brake lines are all fluid-filled (no air) by having them bled after every pad change. This will ensure all 4 sets complement each other correctly, and give you more even wear for optimum pad wear. I usually change all 4 sets at once, rotor as needed, and bleed the lines. Then I bed the pads, and I'm good until it's time for the next pad change.

Hope that answers your questions. If not, I'm sure google will have more information.

 

Well since I really don't feel like reading the whole thing, I'm going to tell you a simple asnwer:

Generic pads will make noise, there's no way around it. If you buy something a bit more expensive and with a better brand name (hawk) the noise will considerably reduced or completely gone.

 

Also, 04 3.0 (not sure about 1.8 model) has break sensors in the front pads so you should see warning lights first before they completed worn.

 

Thanks guys, another noob question. If I get these pads: http://www.ecstuning.com/Audi-B6_A4-...g/Pads/ES2193/ , does the set come with enough pads for 2 wheels or just 1? One of the pictures shows 4 pads, and as far as I know each wheel uses 2.

 

The set is for front or rear, that is enought for the front two wheels or the rear two wheels.

The ones you show on your link are for the rear two wheels. Keep in mind that you also need an anti rattle compound, you can buy it from your local auto store, so that your pads don't rattle around.

 

Pads always come with a pair which means you only need to order 1 set for either front 2 wheels or rear 2 wheels. The link you shown is for your rear brakes.

Rotor often comes with only 1 wheel NOT a pair unless it indicated sold as a pair.

 

When you change break pads and rotors, do you change the calper for a 2014 Audi Q7 with 47,000 miles on it. Is is warranted to change rotor when you have no break noise and the pads have just reached 2mm.

Harry

 

Calipers last the life of the car unless they fail. Had the originals on my 2.7T when I sold it at 230k miles. But had replaced rotors two times and brakes 4x.