Left front wheel noise?
 

I hand't driven my '02 Boxster for about a week and a half. Yesterday got in and as I was leaving my nieghborhood the left front wheel started making this loud scrapping sound - sort of sounded like metal on metal. It would lessen a bit if I stepped on the brake but it was still there. Car has 35,000 miles. I thought brake pad worn? -- but if it was that wouldn't the sensor light up on my dash as well prior to it getting this bad?

then a few minutes later it stopped and I couldn't get the sound to do it again. When I got home, I jacked up the car, and the wheel spun freely - no noise.

Could a rock gotten stuck somewhere it shouldn't? Any ideas?

thanks

Rock wedged between pad and rotor
 

I have had the same thing happen to me, it sounded aweful and abruptly went away too. Keep a close ear on the situation to see if it occurs again...

Also, take a flashlight and loot at the caliper and rotor, you should be able to see how much pad is left. That will at least dispell that the sensors are doing their job...

I had the same sound and thought, too, that I might have gotten a rock caught in the brake caliper. The sound also changed or quieted when I applied the brakes. A difference from what you described is that, for me, the sound never totally went away, though it was sometimes subtle. The problem turned out to be the wheel bearing. If the wheel bearing is what's causing your problem, you should take it very seriously. Eventually the bearing will become so warn that the wheel will largely (and suddenly!) disconnect from the hub. At highway speeds, this would be very difficult to control.

I hope this helps you out.

+1 Devilbox
 

Listen to see if the sound occurs again. If so...than it is not a rock caught in the caliper, but more likely pads (check the inside pad too) or a wheel bearing. The wheel bearing makes a "crunching" sound that will alter its frequency at different speeds. I had an Audi A3 that had the bearing go out at 12K miles, so you do not need a lot of miles to have a bad bearing.

Hmm,when my front driver side wheel bearing went out the wheel had a little bit of play when I wiggled it when the car was jacked. It also made a spinning whosh sound according to the speed i drove and felt it in the car itself.

thanks everyone. I'll continue to keep an eye (and ear) on it

Jack up the car and spin the wheel. If you hear grinding that sounds like its coming deep within the assembly, it may be a bearing. Also grabbing the tire at 10 and 2 o'clock and pulling toward you (away from the car) to see if there is any play in the wheel will determine if a bearing is going out.

If you spin the wheel and you hear scraping that comes and goes, you may just have bent the metal shield and its rubbing up against the caliper. I do hope this is what's gone wrong as it's a very easy fix.

The bearing is $$$ in labor. The part is only $40.