Mercedes GLC Clonking and juddering on near full steering lock

[grober]

Sounds like what you are experiencing is a phenomenon known as "torque steer" where differential FWD can apply differing torque to alternate sides causing the car to slip sideways or shimmy --appearing to steer itself in the process and can be unnerving. This is caused by too much front torque or a lack of grip to the front tyre treads. So first question- is your car equipped with winter or all weather tyres at this time of year? This in itself may effect a cure.
OR
Its supposed that the new steering knuckles alter the caster and possibly camber of the front suspension to combat tyre skip on lock. Caster angle effects steering self centering and reducing that may increase a tendancy to torque steer under certain circumstances. However replacing the knuckles may have altered another steering geometry namely toe--they are all inter-related . Changing the caster angle may require a steering realigment --toe-- to re-adjusted to compensate for the new component- perhaps this wasn't done in this case?

 

[DarloDave72]

Thanks grober

No issues before the knuckles were replaced yesterday and they would have had to change the steering geometry to suit the revised parts, therefore I'm guessing it is more to do with your latter explanation and most likely camber or toe settings that have been not set up properly (this isn't my wisdom, after more frantic searching, I picked this up off a tyre manufacturers website which explains exactly the issue I'm experiencing! )

Called the Mercedes Dealer (Sytner Teesside, who have been very good by the way) and they have asked me to bring the car back asap, so I'm now booked back in for this Friday. I will post the result on the thread just in case anyone else falls foul of this particular problem.

Cheers, Dave

 

[DarloDave72]

My apologies for the late update (Xmas and all that malarkey!).

Took the car in, they checked the alignment and told me that it was a 'tiny' bit out so they had done it again (no elaboration on the exact issue or any digital readout to show me! ). Then went out for a drive with a technician in the passenger seat over some rough roads (easier to find in the UK these days) and hey presto, the unnerving shimmying had disappeared completely. I'd hate to see what happens when the alignment is more than just a 'tiny' bit out, I feel as though the dealer was being economical with the truth and that the alignment was way out after they changed the steering knuckles!