V8matt

Hi All,

I have a 30k 2020 Mercedes GLC, it had a bad squeak/creak from the front suspension (only when going over full width speedbumps, or turning onto an uneven surface)

Mercedes (under warranty) found play in the two lower control arms the (one with a ball joint and 2 other joints), plus both front struts/top mounts.

So all of that has been replaced, but there is still a squeak (albeit initially less than before, but now it's 10 degrees celcius in the UK, it's back just as loud.).

Any idea what else it could be? The service rep seems bemused, as apparently they have never changed top wishbones on these, and he thought that was about it to these cars. Until I pointed out the other simpler lower arm, presumably a sway bar/anti roll bar and the drop links...

I am sure I am not mad, as no other car I have driven squeaks like this on this road, if you go over a uneven road it will just squeak away with that noise all day long. I am wondering if it's the sway bar/anti roll bar given it's particularly picky when going over full width bumps normally (i.e when both ends of the bar are compressed).

I am going out with a senior mechanic in about a weeks time but would like to have an idea what it is.

Matt

mikapen

Interesting problem.
I wonder if your focus on the sway bar drop links is misdirected, based on your "full width" observation.

A full width motion will exercise the sway bar minimally. It comes into effect when L & R suspension moves differently, which twists the sway bar.
If L & R move the same, the sway bar has no effect, although it moves in its central mounting points. The pressure on the end links isn't increased.

Your troubleshooting is on the right track - but I think it has ruled out the sway bar, instead of implicating it.

​​​​​​IF it's full width, it indicates central mounting bushings. Hopefully.