A newbie question here. Hey, out of curiousitty how does one determine your brakes need to be serviced? Every once in a while, when im going slow, like parking, i can hear a very faint squeek from the brakes. Does this mean I need new brakes?

 

No, it means you are going too slow...

Brakes have a life expectancy under normal driving conditions. Under NORMAL driving you would expect pads to last 25K miles +, after which you probably want to check them regularly.

Given the Z, and hard driving by people, expectancy could be shorter. You should still be able to go 10K+ but would have to check regularly for pad thickness, you don't want to score rotors, pads are way cheaper to replace.

Also, due to bias, front go faster than rears, so you can expect to change rears every other turn than you replace the fronts. But again, thats just in general, depends on driving, pads you have on, etc.

A little bit of squeak (you didn't state the miles) could just be moisture or some grease on the pads...

 

Careful -- with Brembos the rears can wear faster than the fronts (mine did). AND, the INSIDE pad wore to nothing while the outside pad still had a decent amount of pad left (the wear indicator wasn't close to the rotor yet).

I'd inspect all the pads closely. The service manual will tell you to replace pads if they have less than 2mm of pad left.

 

2mm of pad...gotcha!! Thats what Im looking for!! Thanks buddy!

 

Good to know. Thanks for your input!

 

Hi H8.

For all I know, not that I am a mechanic, but both events seem like inproper functioning of the brakes.

- There is a bias on the brakes, which makes more force front than rear. For the rears to wear that fast you would have to have some mechanical malfunction or a problem with the proportioning valve. (Or drive with the emergency on, and I won't insult you like that )

- Same with the outside vs inside. I don't know how it would be explained mechanically, but the calipers are designed to apply force evenly. The only way this could happen is the one pad getting stuck too close to the rotor while the other retracts, which would wear that one pad out improperly.

Another possible reason could be a problem with the pads, but that is so unlikely I wouldn't even consider it. Yet, it isn't impossible.

 

I am a mechanic, and what you have said is partially true... However, wear could be different depending on how the car is set up. I don't own a Z (yet, im looking for one) but on the Audi cars I work on the fronts always wear faster than the rear, except on cars equipped with the 6 piston front and 4 piston rear (RS4, and RS6). On those cars, they wear pretty evenly, and i have even seen where the rears have more wear than the front. With these cars, its a simple matter of brake lining compound. In order to get more braking force out of the rear, the engineers at Audi decided to make the rear lining softer, grippier, and subsequently faster wearing.

I will say that the cars that had more wear on the rear were cars that were driven extremely hard. On the second point, I've seen many an inside pad that has been worn much more than the outside. Im not exactly sure what type of system the base and non Brembo Z's have, but it sounds like it is a floating caliper system. It is essentially a one piston caliper that pushes one pad against the disc, then the caliper slides and pulls the other (outer) pad onto the disc. Thus resulting with the inside pad having more contact with the disc and wearing out faster.
-Zach

Edit: And to the OP, the brake squeak could be that the pads are a bit glazed, or dirt, oil or water on the disc or pads. A couple panic stops ~30-0mph in a parking lot should re-seat the pads nicely. I would inspect them to make sure they arent less than 2mm as well.

 

mine sqeak....often...and loudly at times. i had them checked, the mechanic said they had plenty of meat left on em and there was nothing wrong. been like that for about 4 or 5 months but ill live with it until they have to changed

 

Wow, thank you sir. Im meticulous about maintenence on the car so Ill check the pad thickness and then do the harsh stop perhaps. Thanks.

 

Thank you. Mine dont squek often at all. Once in a while and just lightly.

 

Cozmo, a loud squeak like you state can be due to vibration/friction between the caliper and the shims behind the pad. I started using this noise deterrent spray (which is basically a high temp blue glue you paint on) and I haven't had brake squeal in any car in the last 8 to 10 years, including the Z.

Some people will tell you you need to "seat" them, and that might work many times. I seat them also, but use the spray to be safe and it never lets me down.

The good news : is just noise (since you mention the pads are fine). The bad news it is annoying as heck. Taking the pads out, spray and put them back in is a VERY easy job, FYI.

 

No. There is a metal clip inside the pad. When the pad wears, and exposes the clip, you will definitely hear it scrape against the rotor.

 

Awesome. Lots of good info I received here. You guys rock. Thanks!!

 

When driven aggressively, the base Z in particular, can wear the rear brake much faster than the front.

Theories to explain that (other than the simple "rear brakes are too small") is the ABLS (Active Brake Limited Slip) available with TCS and VDC equiped cars will apply brake force to a spinning real wheel(s) to maintain and maximize(sic!) traction.

In other words, guys that floor it all the time (why wouldn't they?) will often wear the rears faster. This will happen even with the TCS/VDC switch OFF since the ABLS is always ON.

To the OP. If it was the wear indicator that made the squealing sound, it would do it regardless of the amount of brake force applied. If the squeal disappear on moderate to hard braking, it's a "normal" behavior of many sport brake pads. Like mentioned, a new bed-in usually solves the squealing (for a time).

 

Guys, all my comments are directed to the normal daily use of the car, and it was stated clearly (see my first post). I drive the car to work every day, in 35mph zones, with traffic lights etc. You know, normal daily driving.

The post that talk about faster rear wear or uneven wear state this happens under "hard driving" and "guys who floor it".

The OP needs to categorize him/herself to know which circumstances apply.

 

My original post stated it ONLY happens when driving very slow, basically when parking. And it is a very faint squeak. I rarely drive the card very hard and when i do, Ive never heard a peep from the brakes. As a matter of fact just last week I was doing about 65 and STOOD on the brakes to avoid an accident. I nearly shat myself but WOW do those breaks work!! Not a bit of fade and total control the whole time.

 

Did you ever tell us if you have a track mdoel with Brembos or the regular brakes? Are you on OEM pads?

 

Chill out man! There were no mean comments directed at you anywhere.

What's "normal driving" on a 300hp RWD sport car anyways?

 

LOL!

I do 0 to 35 in 2 secs and then have to skip 2nd and sometimes third...

 

Non brembo stock brakes.