Steering crack / clicking sound from steering rack / front wheel area

SteveX

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Hi Gents,

I've not contributed to this site for a while so thought I had better!

I've had a cracking / clicking noise from my steering area for a little while now, having inspected everything multiple times (the rack, removed gators, checked splines, driveshafts, drop links, brake discs and calipers etc etc) and replaced, top mounts, bushes, all suspension arms at the front in the past 6 months, the noise was still there (I replaced other parts because they were worn not because of the noise).

I decided to strip everything off again recently determined to locate the sound.

The sound manifests itself as a cracking noise from the front near the inside of the wheels / suspension. It's not a thud, or a clunk, it's like a loud crack or click, only when stationary and moving the rack left to right when the car is still or moving very slowly (IE parking). It can be quite loud and sound like something is broken on the suspension. It can also be felt if you concentrate through the wheel.

If you have a similar sound or symptom for your CLK or C class (and quite possibly any other of the same generation, IE CL, SL etc that has a similar setup) then read on, it may help.

The cause of the cracking / clicking sound in my case was the reinforcement plate and diagonal braces / bolts going to it. As the suspension and car twists slightly under heavy load when still or going very slowly IE parking <5mph, the noise comes from the plate. In my instance the drivers side support bar where it mounted to the steel plate, however, I was taking no chances and decided to completely clean and lube all mounting points.


First you will need to get the car up in the air, either using two jacks with supporting axel stands or ramps / a lift. You do not need to remove the wheels.

Remove the bottom cover, in the case of the CLK held on by six 8mm bolts, 2 at the front corners near the bumper, two in the middle on the outer edge near the roll bar mountings, and two at the rear joining the rear cover:

IMG_6560.JPG

Once removed you will see the supports and the reinforcement plate.

This is held on by four 10mm nuts, two large regular bolts, two different size torx bolts and two female torx sockets (can not recall these sizes sorry). The smaller of the two torque bolts are obscured by the diagonal support struts but you can move these slightly to gain access (one at a time). Remove the bolts and slide it out and remove it without removing the rear mounting covers and bolts for the cross sections.

Here is the plate:

IMG_6548.JPG

Give it a thorough clean and then grease all mounting points and any potential contact points with copper grease or similar:

IMG_6551.JPG

IMG_6550.JPG

IMG_6552.JPG

The underside of the rack, subframe etc was already pretty much clean, but I wire brushed it as well around the mountings just to be sure and also applied copper grease, also clean off the diagonal supports top and bottom, I just used wd40 and a coarse cloth, then also smeared copper grease along the top face :

IMG_6553.JPG

I then manoeuvred the plate back into position:

IMG_6555.JPG

I then put more copper grease on the underside of all mounting holes where the bolts clamp up to.

Above the front section of the plate, make sure you clamp this pipe back onto the underside, also apply grease between the mounting bracket and pipe which is above these mounting holes:

IMG_6557.JPG

The plate back together with everything torqued up and clean:

IMG_6558.JPG

Replace your cover:

IMG_6560.JPG

Drop the car, take it out and test the steering on your drive or road going from lock to lock, if your cause was the same as mine, the sound will now be gone.

It's crazy that this sound can sound like something more serious, and can also be felt on the wheel. Having already been all over the front suspension and steering I knew it couldn't be anything serious, but it had baffled me for a little while.

I've absolutely no doubt that if I had taken the car to mercedes, they would have scratched their head for many hours and probably suggested some suspension or steering components to be replaced!

I hope this helps someone.


Thanks,


Steve
 

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