brake noises 2001 Infiniti G-20

[Ann Duncan]

Hi, I’m new to this site and was hoping someone might be able to help troubleshoot a couple problems with my 2001 Infiniti G20. I’ve taken it to two separate mechanics (several times to one of the mechanics) and no one has been able to identify the problem. I've had the front brake pads replaced, brakes lubricated and the rotors sanded down, but the noises continue.

The most noticeable noise is a sort of grinding/clunking noise that comes from the front-end when I firmly apply the brakes. It almost sounds like I ran over something, and it’s caught up in the front brakes. The mechanic thought this was due to a void in the rotor causing a shimmy, so he sanded down the rotor to even it out. That didn’t work.

I also hear a high-pitched, metallic noise when coasting, which ends when I apply the brake. It comes from underneath the car, around the middle. I know that’s not very specific, but that’s all the detail I can provide.

The car has approx. 40,000 miles and is in great shape otherwise. Anyone have any ideas?

[nametakennow]

Strange, my mom's Mercedes does the grinding thing too.

The metallic noise sounds like you have something rubbing up against your brake disc. I had a chip bag stuck up under my wheel once and it did that. Weird, I know, but that's what it was.

Anyway, it sounds to me like something is doing just that, rubbing against the disc. Possibly your pad is somehow sticking out too far. Especially before being bedded in, new pads make a noise of some kind because they just barely graze the disc.

How are your tires? Worn out tires can cause additional noise under braking, this is the noise I mentioned that Mercedes having, and I firmly believe it's related to the very worn tires.

The other possiblity for the coasting noise is that something is hanging off the bottom of the car, maybe a piece of debris or something.

Hope that gives a few more ideas on what to check. Welcome to NICO!

[RED_DET]

Check to make sure the dust shield it not rubbing on the rotor. This will cause a grinding type noise, continuously. How does the vehicle feel under braking, if you were to let go of the steering wheel, does the vehicle veer left or right? You might simply need new rotors. They can only be turned to resurface unitl a certain point. This all depending on how bad the brake pads detroyed the rotor as well.

[IndyG20]

the G20 pads have "squeelers" integrated into their construction, this could be the screeching you hear. (squeelers are little pins of metal that become exposed as the material on the brake pad wears down, so when the brakes begin to squeel they should be changed). assuming it is your squeelers screaming, and the brakes are grabbing, i would say the pad is gone, and the caliper is pressing the piston directly onto the rotor. this happened to my '93.5 G20, its an easy fix, new pad & rotor on the left rear wheel.

[RED_DET]

He said he already replaced the front brake pads and the noise is still there.