roetundblau

Does anyone know exactly what causes a front brake pad squeak or squeal? And is there a permanent fix for it?

Last July, when I bought my '03 S8 (with 37K miles), I had a 500 mile trip home. On the highway, after driving for 15 minutes or so, a slight squeak became apparent from the LF. The squeak was constant in volume and pitch with any speed from 60-80. A light touch on the brake pedal caused the squeak to change in volume, but not pitch. A harder touch would cause it to go away. If I stopped for ten minutes or more, it would take another fifteen minutes of driving for the squeak to re-occur. A month or so after that, I took the car to the dealer where they installed new disks and pads for both L & R front. After two weeks & about 300 miles, the squeak came back on the same LF side, but a bit differently. Now after fifteen minutes of driving, I have to step on the pedal lightly for the squeak to occur. With light pressure, I can get the squeak to be constant. (In a parking lot or garage, it's real handy to have heads turn and avoid my sleak, stylish Audi that squeaks like my old Ford Maverick.) As before, if I stop driving for 5-10 minutes, it still takes 15 minutes of driving and is not speed dependent. It's been back to the dealer four more times since then. (We don't want to see each other any more over this issue.) Even if I stop hard, the squeak occurs instantly and transitionally from the instant the pedal is pressed until the braking grips hard and slows the car. The last time at the dealer they said they referred to a special Audi bulletin with said to face the rotor with a grinder, bevel the edges of the pads, and lube the back of the pads - but this procedure was "only to be used in extreme cases". Now, the squeak is back again after just a couple of hundred miles.

I have read on this forum and elsewhere that the brakes on these cars can sometimes be "troublesome" and "hard to fix". Is this what people were talking about? Or, was that some other braking issue?

My squeaking problem must be more than disks and pads. The RH side, for example, is as quiet as a mouse. Is there something with the caliper, that is a known issue? Can a caliper mount be bent, etc, etc?? What issue could a factory trained tech (at a dealer) overlook?

TOMAS7

I have a 99 A8 with the same issue. There's a bulletin on the Bentley manual about it which I performed. The squeal went away for about two weeks. It's back and yes it's embarrasing.

PaulW

skiwi had a fix for this on his S8....you can try searching or post on look for him on the RS6 forum

icsamerica

I had the same problem with my 2001 S8 and my 2000 A8 with Brembro 4 Pot (porsche 928) calipers. I ended up changing the brake pads three times. I currently have PBR Ceramic pads that have made the squealing tolerable. I only get a subtle but noticeable squeal once in awhile. The two prior pads that squealed like crazy were factory and PAGID. Since the ceramic pads don't have the bite that the Pagids did, i'm going to try the Wagner ThermoQuiet next. The part number for the S8 is MX912A. I have ThermoQuiets on my Lexus RX300 and they are awsome... quiet, and the best bite and feel I ever had on any car.

You can also try anti squeal shims, go to http://www.automotion.com and search for antisqueal, a weltmaster part should come up. You will have to trim them to fit. I ordered them and was impressed with their composition but I never installed them because my squealing lessened over time and was tolerable with the creamic pads.

mcarcane

mine only squeaks in reverse...guess i got luckey

skiwi

i spent a lot of time thinking that it was the rear brakes as the squeal would go away with the slight application of the handbrake. cue dealer to replace rear pads. no fix. further investigation by the dealer (think hoist, car in-gear running @ a virtual 100km/hr) revealed that the noise was in fact coming from both front brakes - thought to be a vibration of the pads against the pistons. the dealer then replaced both rotors and pads and the noise departed. that "fix" lasted probably 5k kms, and then re-occurred about the time a nice black rs6 slunk across my path.

i believe that this is a problem with all s8's with the 17" brembo calliper - no reason for the issue to affect the teves 360mm calliper. i looked for any option changes to the pads, but there appear to be none.

hth

Perpetual Novice

It would only happen when the brakes had warmed up in traffic. Press harder and it goes away.

Last night I replaced my front pads again, this time with PBR Ceramic. While I was in there I sanded both rotors with 100 grit paper, Lubed the carriers with lithium, and sprayed permatex brake quiet on the backs of the pads before reassembly. I cleaned the rotors very carefully after sanding and then again after reassembly.

So far no squeal, but its only been 20 miles so far.