One of my wife's GL550 snow tire/wheel is getting a rusty brown buildup and I can't figure out the cause. I don't see any oil leakage and the suspension is working properly. The only thing I did notice is when the car is moving in the parking lot I can hear metal friction noise coming from that corner. Does anyone know what this is? The car has 52000 miles and flawless so far.

John

 

Sounds like the brake pad on that wheel is down into the metal backing. Sometimes the semi-metallic pads will create brake dust that can turn rusty, but that looks like more metal than just the normal pad. Combined with the noise you describe, I think you've worn through the pad.

 

Pull it off and see what you see.

 

Worn pad or rubbing pad (as you'd expect them to wear equally to some degree) so a stuck or seized calliper is probably your issue.

 

Thanks guys for the response. I took it to the local shop and right away the shop foreman said it is likely a stuck caliper pin or pads. I will find out for sure later today.

John