jkowtko

If you haven't replaced the steering rack bushings, you should. It's pretty easy ... I created a DIY thread for this ... https://mbworld.org/forums/c-class-w...iy-w-pics.html

crembz

Thanks mate I'll look into it. Hopefully that solves it because I hear the steering column replacement is not a cheap fix.

VVF

Sounds like what I have too.
Did you listen with an open window - mine makes a metallic clanking sound as well as the hollow sound in the steering column.
Also when I rock the driver's side wheel side-to-side there is some noise in the brake booster area. So it might be the steering column u-joint coming loose(see your shop's comment on tightening some bolt).
I haven't replaced the rack mounts yet, and haven't had an indy look into the noise, but the tie rods look solid to me...

crembz

My tie rods are practically new as are my mounts, caster bushes, shocks, springs etc. I don't think they did anything with the rack. I'll get my Indy to check the rack and u-joint next week when he diagnoses the miss that developed after I installed the new spark plugs, sc pulley and psk.

I haven't noticed any metallic sounds. My noise comes up even with the steering wheel dead straight over a rough surface.

crembz

I think it's 25a and 25b which my suspension guy is talking about. You can also see the u-joint here which would require the entire coupler to be replaced.

VVF

Yep, that's it.
And those joints are like $250 used... I've been thinking about it for some time.

crembz

Funny thing is my 05 c200k has the same loose steering column as the c32 buy no unusual noise going over bumps like the c32. It's nice and quite and hasn't had any suspension work done.

My c200k has the sports pack which looks like a similar brake and suspension setup to the c32 so I'm no longer sure the noise in the c32 is in fact the steering column. Only difference between the two is the c32 is running 18" wheels. I suspect something else is loose which is manifesting up the steering column and causing the vibration.

jkowtko

I would still check the rack mount bushings ... Noises come from the strangest places.

Take off the front engine cover, have someone wiggle the steering wheel back and forth with the steering wheel lock off, and look at the rack where it mounts to the frame to see if there is any give as the rack takes a load. The bushings should be very tight so if you notice any movement in there at all then chances are the bushings are bad.

crembz

Suspension guys are replacing the sway bar bushings ... They found movement while it was up on the hoist. Worse on the driver's side which is where most of the noise seems to be coming from. I'll report back with the results once they get installed on Thursday

VVF

My sway bar bushings are new (molded into the bar), still have the sound. So replacing may or may not help...

jkowtko

Same here. Replacing the sway bar definitely fixed the speed bump "creak" ... but that was all ...

hanknum

Yep, I mentioned this on post #3.

Good luck and hope that takes care of it.

crembz

Sad to report that the knock is still there. The seat bar bushes do seem to have stabilized the drive somewhat but I'm still getting knocking noises over bumps... Normally when turning/low speed maneuvers across bumps... Like pulling into a driveway. I'm going to swap out the sway bar links next, even though the suspension guys reckon they are still good.

jkowtko

... and then the steering rack bushings At least do the check to see if there is any movement at the mount point.

VVF

crembz,
I would almost bet it's not end links My sway bushings and end links are new and I get this knock. Although the links are cheap and it may be nice to refresh them anyway.

crembz

Benz here want $190 for each end link ... Crooks!

I'm gonna pull the trigger on the two rack bushes ... And may do the end links just to make sure. They're the only two rubber bits left to change.

Other than that I'm thinking the 18" wheels might be the culprit... Transferring additional noise through to the cabin.

jkowtko

There are four rack bushings -- two each side, a top and bottom one I bought Corteco for ~$13 each.

Fingers crossed ...!

(Fyi, Lemfoerder sway bar links at Partsgeek ... ~$25 each for non-sport, ~37 sport)

VVF

Please do some testing after the 4 rack bushes before you replace the end links

crembz

Thought I'd report back. Ever since doing the sway bar bushings the clunk noises have intensified and gotten more frequent. I'm now getting popping whenever the suspension unloads... Occasionally even when accelerating and only ever on the right. Not sure whether the bushings have been put in wrong or have come loose. I checked the end links and they're tight enough. I'd suspect shock absorbers/springs but they're only 4 months old. I'll take it back this week and see what they say but was hoping you guys could maybe suggest what they should be checking.

jkowtko

The brackets holding those bushings on are pretty basic ... nothing really in the way of them. I do know that there are many diameters of sway bars for our cars, so I would make sure they got the right ones.

If your car does not have replaceable bushings, i.e. they are molded onto the bar, then you have to replace the whole bar. An attempt to find bushings that fit might end up with a problem.

If your car does have replaceable bushings, then also pay attention to the rib along the middle of the bushing where it seats into the bracket. Some cars have "innies" and some have "outies".

crembz

I visually inspected the bushings and it seems that the split ends of the bushings do not meet up at the rear of the sway bar. There is probably about 3-4 mm gap back there. I didn't get a look at the original ones. Is this normal?

Also moving the sway bar up and down by hand induces a noise at the strutt end of the end link. I'm guessing it is loose but didn't have the tools at hand to tighten.

jkowtko

Offhand it sounds like the bushings they installed are for a smaller diameter bar. As for the rattle in the strut area, not sure where that is coming from ... You don't have to remove the sway bar links, or touch anything else on the suspension, in order to replace the bushings. But maybe they did? Don't assume your auto mechanic did everything correctly.

Can you take a picture of the bushing? Can you also confirm the model and year of your car?

Finally, to measure the diameter of your sway bar, cut a notch out of a piece of cardboard or card stock that fits over the bar exactly, then measure the size of the notch. It should be in the 20-23mm range for the front sway bar.

crembz

I'll take a pic next time I'm under there. The Benz dealer said that there are 20mm and 23mm bushings available for the car. It's a c32, and visually pretty sure it's a 23mm bar. I have new rack bushings going in tomorrow. I'll ask the guys to re-torque everything... Control arm bushings, strut tops, end links and the new sway bar bushings. At the moment I'm actually jealous of the c200k the Mrs has because of how smooth the ride is ... Make me desperately want a smooth ride again!

jkowtko

So you're talking about the C32 then? I thought that sway bar (like mine, C230 Sport) comes with molded bushings now and there are no separate bushings available.

I would suggest you contact your local Mercedes dealership to confirm whether this is the case or not. if it is, then the sway bar with moded bushings is reasonably priced from Mercedes. I bought mine from the local dealership (in the silicon valley, not cheap around here) for under $100.

-- John

crembz

Thanks John. Funnily enough when I called Mercedes they didn't mention needing a new bar, they just said check what size bar you have because 2 sizes come up for my chassis number, 20 and 23mm.