GLC knocking on steering column

[Harrythedog]

I have a very slight knocking on the steering column turning at low speeds like exiting my driveway or a junction. I reported it at last years service and whilst the technician noticed the noise he couldn't detect a fault. MB took the car in and said they stripped the steering mechanism down and lubricated everything and it seemed much better. However the problem has started again despit having covered less than 3k miles since last service.
The car is booked in for a service on Friday and I've reported the fault again but I'm asking if anyone has had a similar problem or suggestions as to what I can ask the techs to do.
May I add that this is NOT a crabbing issue

 

[grober]

Sounds remarkably like a muted version of the crabbing problem- are you running the recommended substitute all weather tyres? A simple thing to try if your tyre/wheel size is the same all round is to swap front to back to see if that changes anything= better or worse?

 

[Harrythedog]

Grover I’ve summers at the moment and use winters as well. It’s very similar vibration to a worn cv joint. When they lubricated it last time the steering felt firmer but now it feels lose. I’m concerned any knocking will cause wear and be expensive when the car’s out of warranty

 

[grober]

You will have an electrical steering rack. If the car's under MB warranty I would press for a replacement rack assembly.

 

[Harrythedog]

Update:
MB have replaced both steering knuckles and the OS drop link, we’ll see if that solves the problem but I have my diubts

 

[grober]

A NEW DESIGN OF STEERING KNUCKLE IS THE MB FIX FOR THE CRABBING ISSUE

Steering Knuckle Anti-clonk Fix

Apologies if I've dragged you here expecting to find details of the fix. I just thought the subject deserved its own thread so all pertinent information can be compiled in one place. I see @Fraser Betts and @Learoy are already booked in for the modification on 3rd and 12th March respectively so...

www.glcforums.com

SEE POST 54 -in thread
It would appear this is what they have gone for

 

[Harrythedog]

A NEW DESIGN OF STEERING KNUCKLE IS THE MB FIX FOR THE CRABBING ISSUE

Steering Knuckle Anti-clonk Fix

Apologies if I've dragged you here expecting to find details of the fix. I just thought the subject deserved its own thread so all pertinent information can be compiled in one place. I see @Fraser Betts and @Learoy are already booked in for the modification on 3rd and 12th March respectively so...

www.glcforums.com

SEE POST 54 -in thread
It would appear this is what they have gone for

Many thanks for that Grober, greatly appreciated, Interesting read
I have to take it back in for a wheel alignment as there machine wasn’t working and they’ve said it’ll take 2 hrs to do it !! They certainly seem economical with the truth but I’m glad it’s been done after reading some of the posts in the link you sent

 

[Harrythedog]

UPDATE
So the knocking was still there when the service was due last month. After much investigation they decided it was a steering control unit, apparently the knocking went when the unit was removed. So it’s now been replaced, car‘s been with them for a week waiting fir the part, so we’ll see how that goes