OK, short version: Driving around earlier today, my wheels started emitting a unholy screeching sound. It isn’t the brakes (I rolled in neutral without the brakes - sound’s still there). The car otherwise runs fine…steering, braking, motion, etc. Just whenever the wheels are in motion, there is a distinct (AND AIR-RAID SIREN LOUD) metal-on-metal sound. Any ideas? Wheel bearings is about the only other thing I can come up with.
Can you come up with the year, make, and model?
I think that it IS the brakes. Most likely you are hearing the Wear Indicators that are molded into the brake pads and are designed to make enough noise so that you actually take the car to a mechanic.
Rolling in neutral w/o braking is not an indication that the brakes are without fault. If the noise goes away when you hit the brakes, that reinforces the probability that you are hearing the brake Wear Indicators.
As to wheel bearings–Did you check to see if the bearings are hot? I would suggest caution, just in case you do have hot bearings, but this is something to check before going to a mechanic, unless you are capable of doing a brake job or a bearing replacement yourself.
Incidentally, if the noise suddenly goes away, that means that the brake pads are now so worn that even the wear indicators are gone.
Also, I meant to add earlier, this is a 2003 Honda CRV with about 85K miles on it. Brakes were replaced about 6 months ago and are working just fine. I also have isolated this issue to the front left wheel of the vehicle.
Tester, you beat me to it. Info is added below my original post.
You can check for a bad wheel bearing.
Jack up the vehicle so the tire is off the ground for the wheel bearing you want to check. Grab the tire at the 6:00 and 12:00 oclock positions, and try rocking the tire in and out. If the tire has any play, that wheel bearing is bad.