Knocking on steering on new GLC

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Given the really damp weather we have had, on the odd occasion I've had what I would call tyre scrub as opposed knocking.

In damp conditions on a slow full lock manoeuvre I can feel the tyre slip sideways ever so slightly, can make a bit of noise but not knocking.

I've found wet paving blocks seem to be the worst for it and where I live the entire road is block paving.

However the farther in laws ML does this too, he has the optional 21inch wheels fitted. And the A45 we have also does it with the optional 19inch wheels.
 
Given the really damp weather we have had, on the odd occasion I've had what I would call tyre scrub as opposed knocking.

In damp conditions on a slow full lock manoeuvre I can feel the tyre slip sideways ever so slightly, can make a bit of noise but not knocking.

I've found wet paving blocks seem to be the worst for it and where I live the entire road is block paving.

However the farther in laws ML does this too, he has the optional 21inch wheels fitted. And the A45 we have also does it with the optional 19inch wheels.

Mine does exactly the same as does the Mother-in-laws GLC. I tried to explain to her that it's just something that all GLC drivers are experiencing but she booked it back in to be checked regardless. Mercedes have come up with exactly the comments as described on here and apparently it'll be less obvious with temperatures above 10 degrees or so.
 
I think is a problem with the front differential as I have videoed mine and the inside wheel jumps and rotates. The inner wheel should be free to rotate at its own speed if the differential is working correctly. One service manager at a main dealer has told me he has seen 5 in the last 2 weeks.
 
As my car is with the dealer on Friday I may just mention this as to add feedback on what a dealers response is.
 
I'll see if it's noticeable on my collection test drive on Tuesday, will ask if they have heard about it also just out of interest.
 
I am picking up a 220 Sport in 3 weeks - So I am watching this space and wondering if I should have a talk with the dealer before signing the paper work!

Also note that some of you seem to have run flats - I know there is no spare but are all GLC on run flats or only just the big AMG rims?
 
I think is a problem with the front differential as I have videoed mine and the inside wheel jumps and rotates. The inner wheel should be free to rotate at its own speed if the differential is working correctly. One service manager at a main dealer has told me he has seen 5 in the last 2 weeks.

Did he mention if he resolved any of those 5 ?
 
So I thought I resurrect this thread to see if anything ever came of it.

I'm now pretty much 8.5 months and 7500 miles into owning my GLC 250 with 20s. I had some trepidation when picking the car up after reading this thread and some relief when I didn't seem to suffer the symptoms, OK there was a slide 'judder' but nothing more than any other 4x4 I have owned.

Recently (last week or so) this has changed and the 'jump' sensation has become considerably more noticeable, like 'WTF is it doing' noticeable, it is still a slow speed manoeuvring issue and appears at near to or on full lock (say 3/4 lock onward). This has kind of coincided with the crappy weather, leaf fall etc so wondering if the slipperiness of the roads is amplifying it, however it seems considerably worse on right hand full lock than left hand which is making me wonder if something is up.

I'm going to book it into the dealer for a week or so time when I'm back from a business trip but wanted to check here if this ever went anywhere for anyone experiencing it?

Cheer,

James.
 
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That does not sound right. Most of my manouvering has been on my drive, which has a loose surface, but I have parked in a couple of tight car parks, and I always reverse in, with no sign of any strange behaviour. Can you replicate this parking in the dealership, then you could perhaps do the same manouvere in a demonstrator, or at least show a mechanic.

Personally I am having issues with the ILS, which have failed on two of my four night trips, how ever fancy they might be I do need to be able to rely on them.

Your car has Instrument Landing System ? Impressive !
 
Mine was lifted yesterday. Got a call in the evening to say that they could hear/feel the issue. They tried a stock GLC and it did the same, said it was actually a bit worse, might be because it was on 19".

Tech guy said it was the nature of 4x4 and to do with how the differiential operated.

I'm not techy enough to argue that point but

a) if it is, then why even test it in another car, all Merc 4x4 should do it.
b) My 4x4 XC60 didn't do it.

I've asked them to double check if there is an known issue on the system. But looks like this is something they deem as normal.

Good point - Mercedes have made 4x4 for years : G Wagens ; W124 with 4-Matic ; ML series and I've never heard of this issue before .

Perhaps there is a design flaw with the GLC and the turning circle is just too tight - as it was with the Triumph Herald which would scrub front tyres sideways on full lock .
 
Glc juddering/clucking problem

I'm having the same problem. it only started when the temperature dropped below 10c. Mercedes-Benz have told me to change the tyres to winter tyres. Hope it solves the problem.
 
I'm having the same problem. it only started when the temperature dropped below 10c. Mercedes-Benz have told me to change the tyres to winter tyres. Hope it solves the problem.

They have told you to change the tyres? Are they having a laugh? Much as a winter set of tyres isn't a bad idea that's a hell of an outlay which may or may not solve the 'issue' on a 40k car manufactured by them and behaving in an abnormal manner......I can't begin to thing what I would say if they suggest that....other than OK you put the winter boots on it and if it works I will think about paying some of the cost.
 
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Juddering/cluncking noise

For me it has only started to happen when the temperature dropped. the merc garage did a full investigation, but couldn't find the fault. So they sent a video and report to Germany. The head office there said to change the tyres to winter spec. Will change the tyres next week and give you all an update.
 
My GLC 250 AMG has done this clunking at full lock from new in March 2016, its wearing away at the tyres on the outside tyre rim. It seems to be worse in wet conditions and only on firm ground. It's going in for a week next week so that an investigation can be made.
I'm not happy with a £40k new car turning heads and receiving comments for the wrong reason.
 
I have said this before on this forum!! I will say it again. In the 4WD world, front wheel chipping/hopping/juddering, at low speed cornering, is caused by diff/transmission locking and subsequent wind up.

On loose or slippy surfaces it goes unnoticed (as it should) as the inner and outer wheels are able to match their opposites speed/rotation = 4WD.

When chipping happens on dry ground? it is considered BAD. The usual cure being to switch off the diff lock, reverse backwards in a straight line to unwind the trans etc.

The effect is amplified by big nobbly tyres.

What worries me here, is the fact that some report "no chipping" while others have it and this includes dealers who are pulling cars apart.

Why would MB not make a statement "it is normal and acceptable"? if indeed it is? Why have dealers pulling cars apart and customers complaining when they could simply (as they do with other " false truths" ) just say what the solution is. Even if that solution is "live with it".

I speak as long term owner of a multitude of 4WD cars and trucks that I have raced & rallied as well as used for pleasure. This includes my current 300TE 4-Matic that has this issue and I have been assured that it is 100% not correct!!!! when I turn off 4WD the chipping stops, as it does in my Pajero and Discovery.
 
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I have said this before on this forum!! I will say it again. In the 4WD world, front wheel chipping/hopping/juddering, at low speed cornering, is caused by diff/transmission locking and subsequent wind up.

On loose or slippy surfaces it goes unnoticed (as it should) as the inner and outer wheels are able to match their opposites speed/rotation = 4WD.

When chipping happens on dry ground? it is considered BAD. The usual cure being to switch off the diff lock, reverse backwards in a straight line to unwind the trans etc.

The effect is amplified by big nobbly tyres.

What worries me here, is the fact that some report "no chipping" while others have it and this includes dealers who are pulling cars apart.

Why would MB not make a statement "it is normal and acceptable"? if indeed it is? Why have dealers pulling cars apart and customers complaining when they could simply (as they do with other " false truths" ) just say what the solution is. Even if that solution is "live with it".

I speak as long term owner of a multitude of 4WD cars and trucks that I have raced & rallied as well as used for pleasure. This includes my current 300TE 4-Matic that has this issue and I have been assured that it is 100% not correct!!!! when I turn off 4WD the chipping stops, as it does in my Pajero and Discovery.


I agree I've had this before on a Disco 3 and an XC90, even a Superb V6 4x4 to some degree, however never in the same league of annoyance it is on the GLC, also it was always a constant across conditions and direction of lock which is not the case on the GLC

It does seem strange that if this is a case of 'paranoid owners' that Mercedes are not aware and have seemingly not informed Mercedes dealers of the relevant fobbing off procedure, makes you wonder what's really going on here (if anything).
 
.....and if it is "normal" why is it that in "identical cars" one does it and one does not?

I fully accept that there is always room for some very light vibration and scrubbing on any car in low speed, full lock, cornering on a dry tarmac, concrete surface.

But what is being described here is cars that are " jumping, juddering, hopping"etc on wet loose surfaces, where the diff lock effect should be lost as competing wheels lose traction.

If the competing wheels cannot lose traction? that suggests that they are indeed locked across the axle/diff. That does cause a very noticeable judder and in some instances jumping. In a Disco it is not uncommon for that to lead very quickly to broken shafts or transfer case. It usually occurs where the 4WD is switchable by the driver and the switches get clogged with muck so stop working. This leads the car being left with the diff locked, fine in a muddy field as you will not notice it. But when you get back onto tarmac and try cornering it will judder.

Maybe it is a characteristic of this car? But I say again. Why not on every car in this range?
 
.....and if it is "normal" why is it that in "identical cars" one does it and one does not?
My suspicion is that there is one definite at play (and this really is a "characteristic" of the vehicle), and another possible that may or may not be present.

First the definite characteristic.

My both my first and my current 2WD W212 E63 exhibit quite pronounced juddering and jumping at slow speed on full lock under particular circumstances. In warm conditions with new front tyres it's hardly perceptible, but as the tyres wear it becomes more prominent. On cold tarmac with worn tyres it's very pronounced, so much so that if you didn't realise what the cause was, you'd be heading to the dealer to get it sorted out. This juddering and jumping is a function of the steering geometry and wide, low-profile, tyres with stiff sidewalls. It's pertinent to note that my previous W212 E350CDI on 245/45 17 tyres did not exhibit this trait, except on very low grip surfaces such as snow / slush.

The steering geometry on modern MB passenger cars is fairly similar, so it's reasonable to expect that a GLC with wide, low-profile, tyres will exhibit the same trait. This was confirmed on the other thread about this by Tony Bones from Wheels in Motion.

Now the possible.

I have no experience of 4WD car ownership, but just a simple understanding of mechanics leads me to the view that inappropriate torque biasing caused by a locked or partially locked diff will cause an issue. This corresponds with Bruce's experience / explanation above. It's possible that a control system fault or a mechanical fault could cause this.

So, we have one causal factor that is definitely present and is a function of the steering geometry and tyre size. It will be less or more obvious on any given vehicle depending upon ambient temperature and tyre wear, and this of itself will give rise to ostensibly identical vehicles behaving differently. We also have a potential fault condition that may or may not be present.
 
As several members on this forum may have already gathered ;) I'm not a fan of the "they all do that sir" answer to questions raised by car owners but as always engineering is a series of choices/ compromises. My guess its something to do with suspension geometry, Ackerman and possibly drive shaft articulation. I remember being surprised by the very poor steering lock on a Subari Legacy Spec B a few years back till I realised it might be engineeering compromise due to the 4wd system. Perhaps if MB had put narrower limits on its steering articulation it could have avoided the effect described. Said affects being amplified by wide low profile tyres due to their lack of sidewall flexibility. The suggestion to fit winter tyres in cold weather is not as trivial as it appears. Winter tyres retain greater tread and sidewall flexibility [ hence movement] at low temperatures and will thus mask the engineeering compromise more effectively. :dk:
 
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The suggestion to fit winter tyres in cold weather is not as trivial as it appears. Winter tyres retain greater tread and sidewall flexibility [ hence movement] at low temperatures and will thus mask the engineeering compromise more effectively. :dk:
I agree. I'd make a small wager that fitting new winter tyres will "fix" the problem.
 

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