Faint metal scraping

[djkronik57]

Just bought a 2008 HSE with 87k miles and recently I've been noticing at about 20mph I can hear what sounds like something lightly scraping a brake rotor in the cabin. At higher speeds I can't hear it (possibly drowned out by wind/tires) and can't really notice it at slower speeds.

I've done a little searching and the main conclusion seems to be that it could possibly be a diff going bad.Diff oils were changed at about 70k miles by the previous owner. I'd like to hope it's not, but if it is, what will that cost to replace?

I did also notice sometimes if I have the parking brake engaged, disengage it, and start to reverse, I get a squeaking as I back up. It goes away when I start driving forward. Could it be the parking brake is not adjusted correctly and rubbing?

 

[whydahdvr]

Sounds like the pads are worn down. I've had that sound when the brake pads are low but haven't tripped the sensor yet.
Sometimes pebbles get stuck too and end up scoring the rotors. The squeaking could just be brake dust that has built up. My independent shop folks recommended washing my LR3 every week, especially as I commute to work - lots of stop and go. That builds up the brake dust and contributes to the low speed squeaking.

 

[djkronik57]

I thought it might be the pads as well, but they were replaced (front and rear) recently and have plenty of life on them. I'll double check the brakes just to be safe.

Oddly enough, two other LR3's that I test drove had this same exact noise, so I figured it might be normal?

 

[roverman]

You might want to check and see if it's the metal dust shields. It's pretty easy to hit and bend those (like when you're changing brakes ) so that it just barely scrapes on the rotor. Hope it's this, because it takes about 3 seconds to fix. Look for a shinier groove than the rest of the surface on the inboard side of the rotor..

Other alternative is wheel hubs. Mine at first were faint squeaks, a little louder on turns. Couldn't hear it over 20 or 30 from road noise. That'll get worse soon enough and diagnosis itself if that's what it is.

 

[djkronik57]

So the verdict from an independent mechanic was that the noise was the brake pads rubbing on the rusty rotor. I suppose this makes sense, as the pads were replaced recently and are plenty thick, but the rotors were not and still have a bit of a rusty lip on the edge. The other LR3's I test drove that had the noise were in a similar state: brand new pads on older rotors.

Should I bother with new rotors? Is it advisable to try to sand/brush some of the rust off?

 

[Airstream345]

Your mechanic could "turn" the rotors - eliminating the lip (assuming the rotors still had enough material to turn them) otherwise a significant lip might indicate it's overdue for rotor replacement.

https://www.youtube.com/watch?v=e11G6hNRhqg

 

[asmitty911]

If the problem continues or gets worse you should check the bearings on your hubs. Mine when out and it started by sounding like exactly what you said. I thought it was just the pads rubbing, then i thought it was the dust shield bent and hitting. Found out at 3am on my way texas in the middle of nowhere Louisiana that it was the bearings and they had finally given in and broken lose. It cause the wheel to be able to move freely left and right which destroyed the differential, rotors, pads, and a few other things. I believe its to not much get the bearings replaced but if you end up like me its about $4k problem.