Dave B

iTrader: (2)

If your G35/350Z suffers from excessive front brake squeal, this may be the fix for you. I've owned my G35 for over 3 years now. I've noticed that as the miles progress on the pads and rotors, the brake squeal becomes louder and more excessive under initial pedal application. As most of us know, the standard 03/04 brakes have very aggressive pads that cut into rotors. This why the brakes work extremely well and also why they wear out in about 30K miles. This heavy wear on the rotor is the culprit. For years I was convinced the sound was coming from loose pad shims and I'd screw around with them hoping to end the annoying squeal. It turns out the shims aren't the problem at all.

Here's the problem. As the rotors wear, they develop a lip on the outer and inner portions of the rotor. The pad ends sitting inbetween these two lips. When the pad is lightly applied, the pad has very slight movement and it ends up vibrating up against these lips. Picture one shows the wear on upper and lower edges of the pad where is contacts lip of the rotor. Picture two shows the lip on the rotor.

Picture #1


Picture #2



The fix? It's simple. Mill down the upper and lower edges of the pads to keep the pad from contacting the formed lip of the rotor. I used a air grinder, but the pads are soft enough that a Dremel should do it. You only need to mill about 1mm. It took me about 10 seconds per pad to mill. The squeal is gone.

Picture #3 (milled pad)

VO...

iTrader: (25)

Thank you for the write-up sir. However, I will have to respectfully disagree with the idea that the brake pad rubbing on the outer rotor's elevated edge is what is causing the squeaking noise. It is coincidental however that by milling down the edge of the pad remedied the situation. In technical terms, it is called "chamfering". Alot of high performance brake pad manufacturers will do this to their pads to change the harmonics of it, or the vibration so to speak. It is usually milled down on the leading and trailing edges of the pads however. I could be wrong, as I am not an expert. Just giving my bit of knowledge as it was handed down to me...

Barzten1

iTrader: (18)

Yeah my original AP BBK pads squeeled from day one. The brake kit performed in a big way and I think saved my azz at least twice but they were obnoxious in stop light go-to-go traffic. I thought they were supposed to be like that since I never had a big brake kit and they performed so well. The original pads lasted forever (don't know what brand) with hard abuse and 3 years of the Vortech SC. I finally had to change the pads. Went with Ferredo pads and even changed and bedded them myself. Same performance no squeele. Maybe you just need to change the pads and make sure they are bedded right.

Dave B

iTrader: (2)

I think chamfering is the correct term. Brake squeal can be caused by a lot of different things and you're correct, it's almost always related to harmonics. Often, the source of the problem is shims or other pads hardware components vibrating. The reason I deduced that the rotor wear was causing the noise was because the same noise occured at the same time in terms of mileage on my last set of pads and rotors. The squealing had gotten so annoying that I replaced the pads and rotors early. When everything was replaced, the noise was gone.

As you know, as the miles accumulate, the pads eat into the rotors quite deeply. The pads are floating and they do have slight lateral movement inside the caliper. When the rotor is worn, the pad essentially becomes embedded into the rotor because it's stuck between the two lips of worn rotor. Removing the pad from the caliper and placing it against the worn rotor revealed that there is absolutely no lateral movement available to the pad. I then looked at the pad and could see wear along the leading edges. My guess was that when the brakes are lightly applied, the pads can't move like they normally do and somewhere a harmonic vibration occurs in the caliper hardware or along the edges of the pad/rotor. By chamfering the edges of the pad, the pad can now move laterally like when they were new and the noise is gone.

In the past and on numerous occassions, I was convinced that the noise was simply the shims vibrating. I'd remove the pads and reapply shim anti-squeal only to have the problem reoccur in about 10 miles. I've driven for 80 miles now with no brake squeal.

Dave B

iTrader: (2)

The pads have about 5K miles left in them, maybe more. The rotors are getting close to their service life. The pads were bedded. I make sure to do that with every pad change.

VO...

iTrader: (25)

Agreed. A good observation as well as a good educated fix...

I agree, anti-squeal never really works. At least in my case it didn't either. I have a write-up I composed on rear brake pads and the numerous fixes I tried, only to fail at all. I ended up replacing the pads with a less agressive set in the end. This solved the problem. Our problems were different however. My squeal was caused by a high performance pad that was never reaching operating temperature.

Let me see if I can find the link and post it...