pmathews

Has anyone experienced a popping sound when the cabriolet chassis is flexed, for example, when I back out of my driveway, while turning I hear a single 'pop' (a dull sound). I'm guessing it's related to the cross members under the car, but I tried tightening these over the weekend, and they were very, very tight. Any ideas on what might be causing this?

My ball joints are good, so I know that's not the problem. Also, I'm keeping a constant steering angle while turning, so I don't think it's related to the wheels hitting the frame or bump stops. Also, I'm not bouncing when this happens. My tire wear patterns are really even, nothing unusual there.

I believe it's related to chassis flex in the cabriolet. Nothing super serious, just makes me wonder if I should be tightening or checking something. Perhaps I could weld on a coupe roof (haha).

Thanks in advance... Paul

MarcusF

Have the steering gear bolts ever been retorqued? They're due every 4 years / 50,000 miles.

gregory13lil

You can actually torque them down by turning the steering wheel all the way to the right and then you can access the bolts from the driver side side front tire. They are right there in the wheelwell. Mine were a bit lose and needed to be re-tightened as well. BUT...I didn't have your clicking or popping problem but its worth checking out.

Greg

pmathews

Thanks Marcus for the help, I tried the steering bolts, and they were really, really tight, so I don't think that's it, but it's a good recommendation though, glad I tried it (everyone should do this!).

Greg, thanks for the tip. I was able to cut my wheels to the right and get to the bolts. It's a pretty tight squeeze, but certainly saved me a lot of time, jacking up the car, etc... If my bolts weren't 100% tight, I probably would have pulled the wheel to get an accurate torque reading, but after seeing how wicked tight the bolts were, this was good enough (thanks!).

So, I'm thinking it's a chassis flex thing, maybe I could buy some subframe connectors? The existing subframe pieces under the car look pretty flimsy (the ones that run diagonally from the center of the back frame rail to under the back door frame and from the center of the front frame/crossmember to under the front door frame). Not sure if coupes have these, but if you've got a cab, you know what I'm talking about. These are very tight on my car too (> 80 ft/lbs).

Any more ideas?

Thanks... Paul

clk430convert01

I have a similar front end creaking/flexing problem in my CLK55 convertible. Bought it a few months ago with 20k miles. It happens at slow speeds in parking lots and driveways. Sounds more like suspension motion than body flex. Also tightened up the 4 cross member supports that run diagonal from center body to front/back.... to no avail. Noises as such really take away from the driving thrill. I'll let u know if I ever find the source of this one.

SoCalw11w123

my flex noises come from loose side skirts.... Did you lose any of the lower rivets?

Serndipity

Occasionally, while turning the wheel at slow speeds (e.g. backing out of driveway) I hear a kur-chuck (as though I ran over a small rock).

Feels like it's something in the suspension, not body flex.

the weiner

I get this too in my 209 clk55... its really annoying and It started after I swapped out my suspension, so I am guessing its related, I am going to take it all apart today so If I find something I will post up so hopefully it can help others :fingers crossed:

Just Is

i have a clk 430 coupe with the same issue. it only happens when i back the car out of the drive way with the wheel turned to the left. it started happening a few weeks ago, took the car in to investigate some other issues. had the tie rods, ball joints and steering bushing replaced. i still have the problem though.
i also had a weird stutter when going around an entrance loop today. felt like something was grabbing. dunno if its related though.

pmathews

I looked at my side skirts, and yes, some of the fasteners have failed, so maybe I'm hearing the skirts shift (pop) when the body twists? Does anyone know how to re-fasten these skirts? Where can I buy the fastening hardware?

Thanks everyone for contributing, this whole thread has been very helpful... Paul

lseguy

I've been struggling with this same issue. Dealership and 2 independents can find nothing wrong. Last indy attributed it to a combination of issues: Convertible flex, AMG Stiff sport suspension, my aftermarket 19 inch wheels/tires. Still doesnt set well with me. Entire front suspension has been checked over by all 3 places..all 3 say all bushings and bearings and all else is fine. 2002 CLK55 with 40k on the clock. All OEM except for the wheels.

VIPclk320

the body flex/roll is common on the w208 clk specially in the verts. because of that i manufactored adjustable rear and front strut bars to address this issue, I made a bulk for other members to purchase and still have one set left over, let me know if you are intrested. you can read member feed back and experiences if you search under vipclk320 struttower bars. for the set I can offer you $430 shipped, which includes the front and the rear full adjustable bars, which means you can have all the way from full oem (wobbly) to full track(stiff ride) and all the way in between, they are very easy to adjust to your liking, all you need to adjust them is a screw driver. hope that helped.

lseguy

Realize its years later but thought I'd post my solution. Finally caved in and took it to my local MB dealer. They reporduced the issue and determined that the torx bolts that hold the cross bars (underneath the car and exclusive to the Verts) needed to be tightened a bit beyond factory torque specs. They hit them with the impact gun to tighten each bolt down a bit more...and problem about 90% gone.

Just Is

update as well. My popping ended up being a broken coil in the spring. it was the bottom coil where it was seated. How my mechanics missed that for so long is beyond me

GatorMB

The springs are very stiff in these cars and the spacers do not hide the metal to metal mounting.
I have read one thread with photos about a cracked spring and it warrants an investigation.
I noted the creaking after the car has been lifted and getting quiet after driving and reseating every thing. And after reading through this, the steering gearbox will get re-torqued as well. Thanks Marcus.

All the Best, Gator

GatorMB

Update:
I did an undercar inspection today and did find loose gearbox bolts, 1/2 - 3/4 turn plus torque. Cabriolet supports were loose in 3 areas, front cross-member and right rear rocker mount was hand tight.
Replaced the missing hardware clips in the ground effects and fabbed a jack hole cover out of a scrap Mitsubishi bumper.
Wife is PO !@#,
oh well LOL

Gator

jpfive

This is a great thread - thanks. I noticed the creaking and popping almost immediately on the '02 430 I just bought - less worried about it now.