W11x W108 Drive train noise when turning left

[bracurrie]

At speeds under 60 mph there is no noise with any maneuver. From 60 to 80 mph when turning left somewhat hard, like on an expressway exit or flyway, but not so hard its uncomfortable to passengers, there comes a grinding noise from the center of the car seemingly behind the transmission. IF you cruise at 80 plus mph for ten minutes or so you can just wag the wheel lightly turning the car to the left and the same grinding noise comes from the center of the car seemingly behind the transmission. I've been advised that it could be the right rear axle bearing.
Any thoughts?
All suspension rubber including mounts are less than two years old.

[ja17]

It could be the rear trailing arm mounts, or the center differential mount (in the trunk). On the trailing arm mounts, check to see that the center metal disc is not contacting the trailing arm metal.

[bracurrie]

Thank you Joe for the suggestion. Your wisdom and insights have always been a great help.
The trailing arms look OK. If that had been the problem wouldn't it have shown itself even at lower speeds?
The tightening torque on the center diff mount and the left right alignment strut have not been verified.
BTW I had the occasion driving the car yesterday when I choose to aggressively change lanes to the right from a standstill and the noise came for a fraction of a second as I turned the car left to align it to the new lane while under full throttle accelerating in first gear.
Brad

[Tyler S]

I had a similar noise in a pagoda. The parking brake shoes were adjusted too tight and would rub when turning corners.

[Benz Dr.]

Try turning right from now on. You'll find your way home eventually.

[BHap]

I'm having a similar noise - groaning from rear when turning left - but the noise is evident at low speeds either going straight (intermittent) or especially when turning left. From reading other posts it sounds like it would be the right rear wheel bearing.  One thing I did notice is that the noise can be stopped by applying the brakes. I did recently replace the rear brake pads and rotors so I will make sure the parking brake shoes are adjusted. Any thoughts on whether applying the brakes and getting groaning to stop would confirm or exclude the right rear axle bearing?

[Pawel66]

Look, if it is "tap - tap - tap - tap..." noise while turning on the corner, I had it too. In my case I had slightly too long road wheel bolts (or sometimes they can protrude too far if your orifices in rims get too big after thousands times tightened). They were hitting hand brake shoes. I replaced the bolts with correct ones and the noise is gone.

It was easy to spot as the marks were seen on the tips of the bolts.

[bracurrie]

Benz Dr. thank you for your kind thoughts.  As you probably know I am a road course guy not a NASCAR guy. 
Pawel66 and BHap, thanks for your suggestions. It's not a tap tap tap so no go there. Parking brake adjustment could be an easy thing to try.
Brad

[Benz Dr.]

Benz Dr. thank you for your kind thoughts.  As you probably know I am a road course guy not a NASCAR guy. 
Pawel66 and BHap, thanks for your suggestions. It's not a tap tap tap so no go there. Parking brake adjustment could be an easy thing to try.
Brad

NASCAR turns left - most of the time.

[bracurrie]

I should know that, but there are many who don't. 

[BHap]

I adjusted my rear parking brake shoes (just dragging then backed off about 4 teeth) and still have the groaning when I turn left.  Is this an indication that my bearing is bad?  The wheel spins freely and I do not hear any dragging when in the air.  On the road and going straight, there is slight noise sometimes, but always when turning left.  To me it sounds like the left rear wheel is producing the noise, which is opposite of the above descriptions.  Could it be that my left bearing is "loose" and allowing the shoes to move closer to the drum to make slight contact and produce the groan?  The right rear roller bearing was changed last year.

[bracurrie]

Further observations:
I had the opportunity to drive the car over the last several days and I tried pushing in the clutch while the car was making the noise. The noise went away. Reengage the clutch and noise comes back.

[alpina]

Brad, I have a similar noise did you resolve the issue? what was the cause ?

[dunc1]

Hello
Did you ever unearth the culprit ?
I have been having a similar intermittent issue, that never manifests when I pay a visit to the mechanic and we go for a drive around.
The grinding noise seems to emanate from the right side of my footwell area. It can happen after turning, or parking the car and then driving off at slow crawling speeds, or driving on city streets. The sound seems related/connected to the speed that the wheels are rotating. It comes then goes ? I have tried to record with my phone unsuccessfully. It is not a good sound and I imagine all sorts of further damage occurring. I would love to pinpoint what it could be.
Pardon the intrusion on a long dormant post.
Thanks,
Duncan

[bracurrie]

Well the guy who is working on it believes strongly that the throwout bearing that was installed was installed incorrectly. Finishing engine then changing the throwout bearing and we will see.

[dunc1]

Hi
Thanks for responding.
I had to Google "throw-out" bearing - same as a clutch release bearing.
My car is an automatic transmission, so it wouldn't have that but I do suspect trouble could be transmission related, as I feel the noise emanates around my footwell and transmission tunnel.
Good luck with everything on your car.
I'll let you know if I discover the issue on mine - 1969 280SE w111 coupe.
Thanks,
Duncan

[alpina]

Referring to my post above I also was struggling with a similar noise turning left. This was finally resolved by replacing the rear wheel bearings. The was no
evidence of a problem by rocking or spinning the wheel.

[dunc1]

Thank you for the update. I have purchased new wheel bearing kits for all 4 and will report back, when it's back on the road. Hopefully soon.

[bracurrie]

Update:
I got my car back from having the head replaced and the clutch was also replaced. The throw-out bearing wasn't replaced as it was visibly ok.  The grinding noise is still there but it now doesn't occur until I drive ten minutes or so at 85 mph where as before it took 10 minutes at 80mph.
Dunc1 please update your noise after your rear bearing replacement.

[bracurrie]

Is your car a manual? If so would the noise go away when you pushed in the clutch?

[dunc1]

Hello
I've had the car back a couple of weeks and done a few rides around city streets and a short highway run.
So far, no grinding noise - touch wood it won't manifest again, since replacing wheel bearings at front and rear.
I had a bit of a time with the rear bearings, as the pass. side bearing is unique and is a barrel style bearing, rather than balls between the inner and outer rings. I'd bought 2 kits without this knowledge, so did the job twice after reading some sl113 posts with details and correct part numbers and finding the bearing at the classic Mercedes center in long beach. (pass. side rear bearing should be DIN 635 - 20208 spec. part # A 000 981 05 06)
I also found a loose part on the drive shaft - a metal retaining ring - perhaps the clip had come loose - it could freely spin around and potentially cause a noise ?. So affixed it in situ.
Hope your noise reveals the source, or is any of the above.
Looking forward to some happy motoring.
Cheers,
Duncan