Strange clunk when steering right

[Steve119]

Hi all,

My 500E developped a strange clunk in the steering that is hard to diagnose as for now:

When driving at slow speeds and turning right there is a clunk at around 120° steering angle, and then again around 90° when steering back towards center.
It can be felt in the steering wheel, and even slightly pedals, so it's no light clunk anymore. When steering in slow motion at low speeds you can really expect it at a certain angle...

Strange thing is that when stationary and turning left-right... nothing!
Only when in motion. When driving straight ahead also no clunk or other noises when driving over bumps, potholes, ...

Have got it on my lift now, and nothing really to see:

- shock absorbers with topmounts are OEM MB new since 3000km, no leaks, all mounting screws are double checked and tight
- wheel itself turns smooth (and are tight), no bearing noises to be heard. Bearing play is set OK.
- steering arms have no play (also with pliers squeeze test), draglink had some vertical play so replaced with Lemforder (made no change)
- steering box has virtually no play in the straight ahead position. Ofcourse quite a bit when wheels are turned (but that seems normal with these boxes/benz era)
- steering column u-joint at box is tight, checked inbus-bolts. The 3 mounting screws of the box also tight.
- LCA bushes are also new since 3000km.
- Stabi bar has recent new OEM bushes .
- Steering damper is new, but removed it and no change.
- LCA balljoints were done 10.000km ago, MB dealer ordered OEM TRW's (with the black booth, I presume MB quality)
- No broken spring...

Fact that it only happens in motion, and only when turning right at an angle makes me think towards LCA balljoint, but no play to be felt... so I'm a bit baffled.... anyone with experience on their 500? Would be amazed it's in the steering box, but let's hope not.
Wheelbearing? Would be strange that it clunks when steering right with on other noises...

Thanks for the input!

 

[nocfn]

There is a metal cover over one of the joints at the steering linkage. It may be bent and is rubbing upon turning as you suggest. The ball joint can be as well but the cover is easier to review and repair. If the wheels are not loaded, It may be hard to isolate the control arm joints. Steering linkage issues can be felt in the pedals as they are all bolted up to the same substructure. Have you changed the idler arm bushing? That is also a wear item often overlooked. If it is original, buy new MB - its worth the money.

 

[Steve119]

Hi, yes idler arm bushing is new, and heatshield also isn't the cause

 

[nocfn]

:scratches head:

Control arm bushings up front, tight.... You may be right on the ball joints. Torsion bar bushes tight, cross brace tight. Fender liner loose or a cable slapping. I am sure its obvious when you find it. I have had many. good luck.

 

[Steve119]

It really is too hard to be anything plastic or so. It's a metallic clunk, something that jumps....maybe I'll do the lower balljoint for the 40€ it costs...
cross brace already checked yes I've checked all the bolts and nuts there are...

Wheel bearing is still also a doubt, since it only does it when turning the wheel right while driving, but the exact steering angle it happens at makes me less sure.

 

[gsxr]

Note the ball joints must be installed in a certain position, although if they had not been, I'd have expected odd noises 10kkm ago. There's a mark on the ball joint you can look at to check this.

Wheel bearings seem very unlikely in this scenario.

 

[Steve119]

Took out the LCA and with that and the spring removed I turned the steering et voila... left hand shock absorber is the clunk, right at the turning angle it does it while driving. 1y and 3 months old, OEM Benz...

Made in Turkey

 

[Steve119]

 

[gsxr]

Took out the LCA and with that and the spring removed I turned the steering et voila... left hand shock absorber is the clunk, right at the turning angle it does it while driving. 1y and 3 months old, OEM Benz...

Made in Turkey

AAAARGH. The Turkeys are turkeys, huh. That's depressing.

The clunk is confirmed to be coming from inside the strut? Shame on Sachs for changing production countries and not retaining any semblance of quality.

 

[Steve119]

Yes held my hand onto the shock when turning and a clear clunk at the exact angle. Also sounds a bit like an inside spring jumping when listening closer

 

[nocfn]

WOOF nice find. Was this a broken shock returned and resold or was it just a bad one.... Hope you can get it returned under warranty and glad you found the (*&(Y*P@$ problem!

 

[gerryvz]

That was indeed very nice detective work. GSXR-worthy, in fact. Congratulations.

 

[Steve119]

Fitted a new left shock absorber (under warranty!) and the noise is gone!

Also treated it to new steering arms while up in the air (idler, damper, and drag link were already done) so it now has everything new up front