Steering Knuckle Anti-clonk Fix - Page 26

11-03-2019, 09:44 AM

Quote:

Originally Posted by Philamg View Post

The 63S does 0-60 in 3.8 seconds, I would call that a performance car.

My GLC 220 has a 0-60 time of around 2 mins and it’s a suv not built for throwing into corners at high speed is not a performance vehicle and shouldn’t suffer from tyre skipping whereas my A45 suffers from tyre skipping at very low speed when cold but the handling Into corners in my opinion is phenomenal.
As posted there’s lots of performance cars that suffer from this trait ,the 63s is a beast of a car and has impressive straight line speed and a handful into corners At speed but it’s still an SUV ,thought this was a post about steering angles and handling not 0-60s times..
If I owned 63s and it suffered from skipping I’d be more inclined to think that it’s set up this way to try and help in cornering at speed .
I should of characterised the GLC models when posting and excluded the 43 and 63

11-03-2019, 06:59 PM

I had a GLC43 with 367hp that suffered badly from tyre skipping, I now have a GLE 450 with 389hp that doesn't suffer from tyres skipping, the 43 and 63 shouldn't suffer. LHD 43 and 63 models haven't got the issue, I have been involved with this issue for over 3 years and took MB to the motoring ombudsman. ALL RHD GLC's suffered the issue and eventually MB redesigned the steering knuckles for all models except the 43 and 63, if you drove one of these models in wet cold weather you would know just how bad it is.
I mentioned the 0-60 time because you said it wasn't a performance car, you didn't say except the 43 or 63.

You are correct, this is a post about steering knuckles and is 26 pages long, there is also a post on here about crabbing and that is over 100 pages long, it has been a frustration to a lot of forum members for a long time and the reason I didn't buy another 43.

11-04-2019, 02:26 AM

How does one check if they have the new knuckles? (I've asked my dealer for the build sheet and he showed me the only thing he has which mentions key IDs for engine etc but not all the parts for the car)

I've just bought a 2020 model GLC 300 in Australia, and discovered that it's doing something that I believe is crabbing. It's not show stopping, but it's definitely odd/unpleasant and it's happened to me despite the warm weather (and with warmed up tyres) so I'm a little worried it could be much worse when cold.

I'd assumed the issue was fixed in the 2020 models but now I'm not so sure. Tyres are Pirelli Scorpion Verde run flat 20"

11-04-2019, 06:01 AM

All Glc's produced from November 18 should have the new knuckles fitted, my dealer had 1 that was supposed to have them but didn't. Your dealer should be able to look at them and ascertain if they are the new ones.

11-04-2019, 07:08 AM

[QUOTE=

""""BTW, I've been checking this and it seems very prevalent in Porsche and Corvettes. From what I understand, it seems to be an engineering decision made to improve turning radius.

[/QUOTE]

It’s a DESIGN FAULT on all Right Hand Drive GLC’s, that is very different to the characteristic seen on performance cars such as Porsche etc.

Left Hand Drive GLC’s don’t suffer from the same Crabbing & Clonking.

When MB moved the steering wheel from the left, as on the original European GLC, to the right on the UK / AUS markets. They struggled to position the steering components and front differential in the ‘fixed’ engine bay layout. Design and engineering changes were made that resulted in the Crabbing Fault on Right Hand drive GLC’s 😩

MB have not admitted to any differences, but whatever they did has broke and seriously damaged the RHD GLC.

Yes the Knuckle Fix does help fix the fault, but not completely.

Right and Left Hand drive GLC’s have different Front Differentials. There isn’t space in the RH drive engine bay to fit the Diff fitted on the original LH drive version. My opinion is that this difference is the real cause of the Crabbing Fault - This cannot be fixed without major engine changes, which MB cannot consider retrospectively fixing under warranty. The Knuckle fix results in more tyre contact and grip, that hides the Front Differential fault.

Apart from the crabbing, the GLC really is an excellent car 😊

TM

11-04-2019, 10:31 AM

TONY

MB DID admit to the difference between LHD and RHD in letter sent to dealers in February 2017:

"Further to our interim update last week, we are now able to provide a more detailed technical explanation regarding this issue.

Due to the positioning of the front axle differential on right hand drive cars, the steering position differs very slightly compared to left hand drive models. When the steering is on full lock this steering angle difference can result in the front tyre skipping sensation. This is more pronounced during cold weather and when larger wheels and low profile tyres are fitted. "

11-04-2019, 01:17 PM

Well at long last MB have updated my GLC 220d steering knuckles today under warranty. The fix seems to have done the job as I have 20” low profile AMG wheels and the outside temperature is only circa 9 degs C. The roads are very damp too. Under these conditions the car normally does a hop, skip and jump when I go around a local roundabout, or if I do a 3 point turn in our cul-de-sac. So far so good, no sign of tyre skipping.
Now for the bad news, The MB Stealership admitted that they had damaged my NSF wheel arch whilst they were replacing the knuckles and have had to order the part in from Germany! I suppose I should be thankful that they admitted it and I did not have a fight on my hands. Now I have to wait for the part to arrive and for MB to ring me.

11-04-2019, 05:42 PM

For those with a pre-facelift car on the new knuckles... are any of you on original spec tyres or have you also switched away from run flats? Did the problem get 100% resolved or just reduced to not a nuisance? (I'm certain the knuckles fix the main cause I'm just also wondering how much part tyres play).

Philamg I'll try and get a look at the knuckles installed on the car (although without a supplied jack that might be difficult ��)

11-04-2019, 06:22 PM

Thanks Phil - I was not aware of this info from MB.

MB have also fitted different Front Differentials on our right hand drive GLC’s. The non-crabbing left hand drive cars are fitted with Double Planetary Gear Diff’s, which apparently give smoother motion transfer.

It’s impossible for them to make changes to the wheel alignment, because the wheels would not fit centrally in the body-wing panels.

The Knuckle Fix changes the angle of the strut, which places more tyre surface in contact with the road. Hiding the fault in the Diff - in my opinion

Our 2016 GLC has had the Knuckle fix and FOC All Season tyres fitted. This has certainly improved - reduced - the Crabbing, but still not 100% gone. Having said that, it’s now virtually unnoticeable and acceptable - even to a longer suffering and complainer 😖

Personally, I could not live with this fault if I owned a C43 or C63 that doesn’t have the option of the Knuckle fix - the Crabbing & Clonking drives you crazy - especially at this time of year 😩

TM

11-04-2019, 06:49 PM

Tony, here is the full letter they sent to the dealers as I haven't posted it for a while. Obviously superceded by knuckle fix but will let new members know how long this went on. You are correct, I couldn't live with the fault, even though they gave me new wheels with winter tyres (as far as I aware nobody else has got this) I didn't want the hassle of changing wheels twice a year, not in the UK climate.

24 February 2017

For the attention of Market Area Directors, Sales Directors, After Sales Directors, General Managers, Sales Managers, After Sales Managers, CSU Managers

Dear Colleague

Further to our interim update last week, we are now able to provide a more detailed technical explanation regarding this issue.

Due to the positioning of the front axle differential on right hand drive cars, the steering position differs very slightly compared to left hand drive models. When the steering is on full lock this steering angle difference can result in the front tyre skipping sensation. This is more pronounced during cold weather and when larger wheels and low profile tyres are fitted.

We can assure you that our technical specialists, as well as independent experts such as DEKRA, concur that the cars remain completely safe to drive.

Fitment of All Season tyres counteracts the sensation. We are therefore securing sufficient stocks of these to provide to customers who find this uncomfortable.

· Mercedes-Benz Cars UK will contact GLC customers who have already registered a Compass complaint:
• Customers with 17”, 18”, 19” and 20” tyres will be offered a set of All Season tyres (once available) and fitment free of charge
• For GLC 43 AMG customers who have cars with 21” tyres, a 21” All Season tyre is not currently available. We will offer these customers the option of taking 20” wheels and All Season tyres, or waiting for 21” All Season tyre availability

· We would ask you to please do the same for GLC customer complaints that you have received and managed locally or for any future GLC complaints about this issue until further notice

· Please also take the following action for customers who have ordered their car but have yet to take delivery, and for future customers of existing dealer and pipeline stock until further notice:
• Please make sure they are aware of this characteristic.
• Customers proceeding with delivery have the option to take All Season tyres as soon as they are available or to wait and change to them if/when they experience this sensation in Winter 2017/18.
• For customers who do not wish to take delivery of their GLC with summer tyres, please offer a courtesy car until the All Season tyres are available for their car.

For all the cases above concerning provision and fitment of All Season tyres, please submit a goodwill claim against damage code 2113800.
We will provide updates concerning any interaction we have with your customers, together with availability of the aftermarket All Season tyres and the logistics process involved.

Yours faithfully

David George Sally Jones
Sales Director Customer Services Director
Mercedes-Benz Cars Mercedes-Benz Cars

Emma Passmoor

Customer Services MBuk

The odd thing was that they couldn't provide all weather tyres for 19 and 20 inch wheels but did provide a BMW sourced tyre for 21 inch wheels, they obviously didn't do their homework before sending the mail.
I have 22 inch wheels on my GLE and no sign at all of crabbing.

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