I drive a 2003 ML500 that currently has 138,000 miles on it.

I replaced the rear pads and rotors about two weeks ago. All was well.

Last night while driving home, I noticed a noise that appeared to come from the right rear wheel area. At first, I thought perhaps I hadn't tightened something correctly when I did the brake work. But then again, it sounded vaguely like a wheel bearing failing, so I was stumped.

Before I had a chance to pull the wheel and investigate, I had to drive somewhere to drop off my daughter - the noise was back and was a bit louder than the previous night. It didn't sound ominous - and I thought I could drive it anywhere without second thought.

So I am returning home and going about 50mph - and I hear what sounded to me like my right rear tire had exploded and that the carcass of the tire was slapping the inside of the wheel well or something. This was LOUD. I pulled over immediately to see what had happened.

Nothing. Everything looked just fine. Which was a good thing, I thought. But what could explain this loud, violent noise that started out of nowhere?

I drove another 100 ft to see if the noise would return and it was as loud and awful as ever. Called a buddy for a ride home and called MB Roadside to have it towed to the dealer.

The _only_ thing that I suspect it could be would one of the rear axle half shafts. The noise was consistent with each tire revolution so it is something in the driveline.

Something seriously "grenaded" back there.

So, it looks like I will be having an expensive conversation with MB of Ft. Mitchell, KY tomorrow.

This ain't good...

Chris

Parking brake mal-adjustment leading to a catastrophic overheating and eventual failure of the pads and maybe the rotor, backing plate.

If the vehicle would move under its own power after the noise it is unlikely a driveline failure i.e. axle shaft