Engapol

I have a 2001 C320 with quite a few miles on it (nearly 100,000) and every time I drive over even the slightest imperfection in the road, I hear a clear creaking sound from the front suspension. On a poor road the creaking is endless, and if I hit a pothole or go over a speedbump at speed, the creaking is incredibly loud. The noise is a sort of a mix between a knock and a creak, it doesn't sound dull.

I just replaced my sway bar bushings, and funnily enough it made the problem slightly worse, the creaking is now louder and more noticeable. I did everything up very tightly during the bushing replacement including the sway bar links.

I jacked it up again and wiggled both front wheels and they made very little noise (almost inaudible), definitely no clunking, and I push and pulled the sway bar links (still attached to the sway bar) and I couldn't budge them. I took a glance at the control arm bushings and they look fine. The dealer said it was my worn shocks and wanted $2000NZD for the job but I can't detect any fluid leaks and the ride doesn't seem compromised.

Sway bar links are still my prime suspect though, how can I see definitively if they are bad?

Boom vang

there is this grey goop that the dealers at MB have to lubricate sway bar bushings, (main reason new bars are made with the bushings moulded in)

This goop is very thick and gooey and solved my creaking when I put in new bushings.

Take off the bar and bushings spread this goop all in the inside of the bushings and on the bar and reinstall.

car sounded like an old wooden sailing ship going over bumps or even the slightest incline like a driveway

Engapol

My MB dealer didn't suggest putting lubrication on the new bushings, they came with this smooth fabric-like lining which apparently does not need lubrication and the tech article on Pelican Parts said to avoid any lube as well, since it would cause the rubber to deteriorate.

Even if it is the bushes still causing the problem, it doesn't explain why the creaking noise is just as bad as before (when I had ancient bushes).

jkowtko

with the car standing still have you tried pushing down on each front fender to exercise the struts and isolate the source of the noise?

Strut top mounts on these cars are made of a big piece of rubber that will creak. Try turning the steering wheel with the front of the car jacked up, see if you get any noise there.

Engapol

I pushed down on the while it was parked, on both sides I noticed a quiet but audible 'clunk' sound when the car was on it's way up after I pushed it down. When you say turn the wheel while it's on jack stands, is that with the engine running? By the way this noise I'm getting appears totally independent of steering and the direction my car is travelling in, even cornering hard on a smooth road doesn't produce any noise.

Anyway, I found this video and it sounds very similar to what I'm experiencing right now. Tomorrow I'm going to remove the links and drive with the sway bar taped to something, hopefully that'll narrow down the list of culprits.

jkowtko

also check the top strut mounts to make sure the rubber isn't completely torn. That bracket that is sitting on top of each mount pocket from inside the engine bay .... when you bounce the car up and down those brackets should barely move (i.e. 1/8" max) with respect to the car body. If they move up and down excessively then you've got bad strut mounts.

It would also be good to put the front wheels on ramps and get someone to lie down under the car while you bounce up and down on the front end. hold a metal rod against various suspension parts to see where the clunk vibration feels loudest.

It would be great if it were just the sway bar links ... probably the easiest and cheapest parts to replace.

Engapol

When I was playing with the tires, the strut assembly was pretty firm, absolutely no play at all and the steering feels precise and smooth when driving, like it should. I opened the hood and couldn't observe or feel any movement of the of the metal or the bracket itself in the engine bay.

The strut mounts (and probably the entire strut assembly) probably aren't in peak condition but they are most definitely not torn.

Boom vang

Lub will deteriorate the bushings if it is a petroleum product but this goop is not that and made as a rubber lube. Our MB dealers in the greater Toronto area are corporate run stores so I think they would be not be using something that is not approved. The tube that they squeezed the goop out was a MB branded part

It would make sense that new bushes would cause creaking as they are tighter than older ones. If your sway bar has rust on the contact points it would cause it to creak.

the strut bearings can creak but you would only notice it turning the steering wheel and really notice it when you are stationary

Engapol

I removed the sway bar links this morning. One of the nuts felt like it was welded to the strut though, took me the good part of a an hour just undoing that. And the noise went away! I took it for a short test drive, took it over curbs at speed and cornered hard, in fact the only noise I can hear now is some very quiet squeaking from the rear suspension (which I couldn't care less about right now), it must've been masked by the louder front suspension all the time.

I ordered a pair from the dealer at $218NZD, and hoping to get it this afternoon for a short roadtrip, but even if they don't get to me on time the car is good to drive without them, I didn't notice the extra body roll until I flung it around. I don't care anymore....the noise is gone!

If the squeak returns when I reattach the sway bar to the strut, I'll take your advice about the lubrication.

Boom vang

$218NZD is crazy for a pair of sway bar links that works out to $194CDN, are they gold platted? Sway bar links are usually the cheapest part of the suspension

I paid around $30 ea for OEM from MB in the US, also available are original equipment Lemfoerder from RM European for about $21US ea. Perhaps you should see if they ship to NZ.

My experience is that links usually don't creak but rather clunk when worn out with the loose ball joint.

I am willing to bet it is still your bushings, it stopped the creaking when you disconnected it because the bar is now not moving within the bushings

I don't think it is particularly safe to drive with the fronts disconnected because you still have the rear connected and you may get severe oversteer without the front connected. You will have to drive like a grandma when going around corners and probably would avoid a highway on/off ramp

KSKarl

Since the sway bar is disconnected, you can work it up and down to see if it creaks.

KSKarl

But you said you heard a clunk noise when bouncing the car. That sounds like sway bar links to me.

jkowtko

He said both clunk and creak. Sounds like both needed to be replaced.

Seems like every little part on these cars make some distinct noise when worn ... it's like a "bucket-o-bolts" synphony Fortunately as you replace each part the associated noise goes away ...

Boom vang

I ended up replacing every part on my front suspension over a couple of years (many were on warranty), for the past year I have no noises and this is the first time other when the car was new that I have a quiet front end. This was when the cross strut and torque strut were replaced for the 2nd time!

jkowtko

Same here ... love these cars! ... but you gotta take care of them

Engapol

There was a clunk noise when I pushed on the car with the old sway bar links still on it. I repeated the test without them and there isn't a clunk noise anymore.

I took the old ones out and they looked pretty bad, the rubber covers that protected the open side of the ball joints had either come loose or deteriorated and cracked. One of them was practically open to the elements (You could clearly see the ball joint with the grey goopy paste inside)

Engapol

I looked at getting them from Pelican parts as well as RM European, while the OEM parts themselves are pretty cheap at around $22USD each, the shipping costs to here are anywhere from $50-$68USD. Taking into account the currency conversion charges and the fact that it would take several weeks to get here, I'm willing to fork out the extra to get them sooner.

Engapol

I replaced the links (finally) without lubing the bushes, a subsequent test drive produced no knocking/creaking so it was definitely the links that were causing it.

I did ask the parts guy at the dealership about the grease and he went to ask the techs but they said they didn't use any on the bushes, can't see why different Benz shops would have different advice, maybe the conditions are just alot more harsh up in Canada?

Glyn M Ruck

Pleased it's sorted. For others that find this.

https://mbworld.org/forums/c-class-w...spension+noise

Jaseon

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doing this worked for me still no noise two months later, I will put new struts in though in the future