I just got home from a 500miles trip and started to hear graveling noises coming from the passenger rear when I came off the freeway exit.
The wheel looks clear as I don't see anything stuck to it. Please listen to the noise in this link and give me your idea of the problem.
https://1drv.ms/v/s!Age2cdd0L6z3hutYZAQBjPmthUEY3w

 

It could be a number of things, brake pads, parking brakes, wheel bearing.

 

I removed the wheel for a closer inspection and noted wet grease between the wheel and the boots so high chances this is bearing problem.
I'm trying to figure out what needs to be replaced with WIS/EPC and don't have much luck. Is this something that needs dealer involvement as it needs to be pressed?

 

You would have to replace the bearing and possibly the flange if it is damaged.

You can have a repair shop do it instead of the dealer.

 

This is potential info for future folks searching for "gravel noise".

Just last week my 2008 ML350 developed a sudden, scary noise that also sounded exactly like gravel. Like it was bouncing and grinding around in a metal box. I thought for sure it was coming from a wheel or the drive train.

But nope! After climbing under the car and poking about, it turned out I had an exhaust clamp rust out and fail. The remaining pieces all rattled in such a way that it sounded exactly like gravel! Replaced the clamp over the weekend and the scary noises were gone.

May not be your issue, especially if it only happens when in motion...but it's worth a look if you hear mysterious "gravel noises" with the engine running.

 

On the ML63, there's an off-road mode that I don't see on ML550. I thought it was on by mistake and high freeway speed killed the system but it wasn't. It just somehow went bad during the drive.
I tried MB specialized independent shops in the past but didn't see much differences compared to dealer. I guess I can give a non MB shop a try to help them out during these difficult time.
[Update]
Stopped by a random shop. The sign said European and Asian but the parking lot was full of Japanese and none of German. Left the car for 2 days and just picked it up. The problem was indeed wheel bearing. Not sure of the exact parts but the cost was $190. The labor cost was $400.

 

I did the differential fluid exchange for front and rear today with MB Hypoid Gear Oil SAE 75W-85. Old oil has coffee color instead of canola oil color so I guess that was a good thing on oil exchange.
Did a 5mph road test with windows down and suddenly I heard grinding noise again from rear passenger side. It didn't sound like the constant graveling noise that I heard before but the noise is definitely there except it happens intermittently...
Lately, I heard of humbling noise and I thought my ears were calibrated to the S class noises. Scheduled a dealer service as I don't think independence shop can fix my problem. I can't live with this humbling noise. If I can get rid of this humbling noise then I will get rid of the car.

 

Nasty sound on the video.

Year and mileage for this vehicle? Off-roading or mountain/forest road driving recently?

Candidates:

- failed caliper piston seal
- failed wheel bearing
- failed axle shaft CV joint
- bent rotor dust shield
- pebble or rock wedged into the rotor

What condition are the brake rotor surfaces? Normal or scratched? This should be obvious.

 

It's 07 with 112k miles. No off-road but that trip involved freeway mountain driving via I-90, I-82 and I-84 from WA to ID.
Wetness were seen between boot and wheel and the shop was supposed to fix the bearing but I'm not sure if they messed it up somehow.
The constant noise is gone after the bearing job so looks like they fix that part of it. CV joint is a possibility in conjunction with the wheel bearing.
The current noise at low speed is so intermittent when no brake applied so I'm ruling out brake components for now.

 

@DrDoe Does the noise change when the vehicle is moving and the brake is lightly applied?

 

Well, I didn't know the answer whether noise would change so I took it out for another drive. Drove around for about 10min and absolutely silent. No noises. I was about to give up then it happened and it seems to be higher frequency as I continue to drive. Applied the brake and I don't think there's a change.
Here's the noises recording from inside the car and with windows down: Inside
Comparing to original recording from outside the car: Outside
Seem like no changes before and after bearing works?

 

@DrDoe did you have the wheel bearing replaced? Your comment above referenced “bearing job”.

If the bearing is new, and you concluded the sound doesn’t change with brake application, the next thing I would look at is the CV joint. Have you firmly held the axle shaft and tried to shake or move it?

 

I had a shop worked on the bearing job. They charged me $180 for bearing parts. The wetness between the boot and the wheel appeared to be gone.
How to test for CV issues?

 

@DrDoe So you have a new wheel bearing? Yes or no

To test the rear axle CV:
- from under the vehicle (safely), firmly grasp the axle shaft and try to move the shaft. Shaft movement indicates a loose CV joint.
- with both rear tires off the ground and unconstrained (parking brake released), rotate the suspect wheel by hand. Notice any noise.
- while driving at a very slow speed, drive diagonally over a bump like a low curb, driveway or speed bump. Allow one tire at a time to travel over the bump. Notice any noise when the suspect wheel travels over the bump
- In a large, empty, flat and smooth parking lot, drive at low speed in a circle. Listen for noise in the suspect wheel. Increase speed while increasing the turning circle diameter. Listen for noise.
- At low-medium speed, drive over a bump or dip with one side of the vehicle (left or right), then repeat with the other side. Listen for noise in the suspect wheel.

If you do all of these test precisely, you will have a good idea of the condition of your CV joints.

 

. Well, The truth is I don't know. The shop worked on it. I can't tell if they did something to it or install new parts.
I do want to learn about testing the CV so I will run the test and report back.

 

I tried to move the axle shaft with only my hands and I don't think there's any movements. Perhaps I need to pry it with something?
Rotated the wheel and didn't hear any loud noises. It does seem to be rubbing against the brake pads. Decided to shake the wheel: Loose wheel. Bearing problem?

 

Loose wheel video. Could new bearing went bad after 100miles or so?

 

Are your lug bolts torqued properly?

 

No. That was the 1st thing I checked.

 

@DrDoe Are your lug nuts tight in the video? Yes or no

Did you post the same video twice? Yes or no

 

Are your lug nuts tight in the video? Yes.
Did you post the same video twice? Yes. I was planned for another video but pasted the same link.

 

@drdoe I would say with very high certainty the wheel bearing is completely failed. The "bearing job" you referred to, can you post the invoice from the shop that did the "work"?

Unless you provide evidence to the contrary, the wheel bearing needs to be replaced.

p.s. I should have said lug *bolts*, not lug nuts. Decades of habit die hard.

 

Here is the invoice:

 

@DrDoe It doesn't seem like the work you paid for was successfully completed, do you?

 

That's what I wonder. If it's indeed bearing then looked like it failed after 100miles or so. I'm very sure that they worked on it and not just paperwork.
So if lug bolts are tight and wheel have movements then bearings and nothing else?