Weird squeek? 99 C2

[Reborn996]

Okay, I have had a weird pulsing squeek sound coming from the rear of my car for a few weeks now... unfortunately I cannot find it without the car moving, so I wanted to run the symptoms by you fine folks to see if you can help.

The sound is wheel speed dependent and coming from the rear (not sure which side but sounds like drivers), is not effected by braking or steering, goes with wheel rotation and not engine rpm (present in all gears), and goes away when under throttle. It is most noticeable when coasting or under deceleration... the minute I hit the gas it goes away. It is not always present but is about 75% of the time. I have PSS9 coilovers but have had them for many months with no issues. Any ideas on what to look for?

My troubleshooting idea on this was to lift the rear of the car and put the rear suspension on jackstands to keep it under load... then start the car (carefully of course) and see if I can hear anything with it in gear.

Anyways, the sound is driving my nuts so any help is appreciated!

David

[Izzy]

Sounds like brake pads or glazing on the rear rotors. I would recommend some emery paper (sand paper for metal) fine grid, and do some light hand sanding of the rear rotors, sand radially (from hub to edge). Do it softly first, spin the wheel to check, do it again. If it is glazing, a few repeat steps will remove or significantly reduce the noise. Check your pads too, make sure they are good.

Another potential is the heat shield over the rotor, which tend to bend and come in contact with the rotor. But that typically happens after a hot track day with heavy braking. If that is the case, I solve that with a long flat screwdriver, push on the shield to it is not in contact with the rotor.

[Reborn996]

I thought about brake pads as well... but applying the brakes makes no change in sound. It is more the throttle actuation that seems to make it come and go which is weird. I was thinking some suspension bushing might be it but not sure. Even thought about the exhaust system couplings since the engine movement under load might cause it to go away under throttle like that.

What about wheel bearings? Would they behave this way if they were going bad?

David

Sounds like brake pads or glazing on the rear rotors. I would recommend some emery paper (sand paper for metal) fine grid, and do some light hand sanding of the rear rotors, sand radially (from hub to edge). Do it softly first, spin the wheel to check, do it again. If it is glazing, a few repeat steps will remove or significantly reduce the noise. Check your pads too, make sure they are good.

Another potential is the heat shield over the rotor, which tend to bend and come in contact with the rotor. But that typically happens after a hot track day with heavy braking. If that is the case, I solve that with a long flat screwdriver, push on the shield to it is not in contact with the rotor.

[Izzy]

You may want to get the car up, remove the wheel, and spin the rotor with the car on neutral. Try to pin point it that way?

[Reborn996]

FYI, finally found out what it was... the wheel bearings! Just replaced all of them and all fixed.

David

You may want to get the car up, remove the wheel, and spin the rotor with the car on neutral. Try to pin point it that way?