jetson

I have a 2009 MB c300 4matic. When turning all the way to driver side there if a knock/clunking sound. It also does it some when hit bigger bumps in road. I have jacked it up and had on a 2 post lift but can’t reproduce the sound. I checked stabilizer links, wheel bearings and control arm bushings but all seem good. Any help appreciate. Thanks

Just204

Good chance it’s strut mounts.

TimC300

To try and reproduce front end noises on mine i'll stand on the side of the car and push the front end down, trying to bounce it. I located a squeek that way, was coming from the top of the strut. I squirted some PB Blaster silicone lubricant all over it, pulled down the dust boot and sprayed in there, even opened the hood and stuck the straw in an opening in the cap at the top of the strut. Im not sure it did anything or it went away on its own.

I'll raise the front end from the middle jacking point, jack stands on the side jacking points. Wheels off. I'll use another floor jack under the wheel carrier and raise and lower it listening for noises. Try this with the steering wheel turned all the way each side.

Grab the control arms and try to rotate them, see if there's excessive play in the bushings.

Stick a pry bar or long screw driver and try to move the ball joints at the wheel carrier.

Worn stabilizer links are easy to check for, you would hear them clunking when driving straight going over bumps/pot holes. if worn they will easily rotate by hand. Inspect the rubber boots for cracks or grease leaking out.

Inspect the struts. Make sure the springs aren't broken. I had a spring break when my car was parked, I actually heard it break from inside my house but had no idea what the sound was, sounded like the crack of a baseball bat hitting a ball. In the morning I noticed the car sitting a little lower on one side, found the spring broke. With the wheels off have someone turn the steering wheel while listening to the strut, may be able to hear the bearing binding if its bad. Grab the strut and try to move it.

jetson

I will try you jack method. Maybe that will reproduce the sound. I tried to push bounce it up and down but had no success. Someone mentioned CV joint but seems unlikely to me. It has to be something in the suspension.

jetson

I put the car up on ramps then turned the wheel. I was able to hear a little of the noise but difficult to isolate it. The stabilizer links seemed loose but not terrible. I am going to start there since they are relatively inexpensive and easy to replace.

Just204

the end links are a known part to cause noise. Definitely not a bad idea to try those, mine went bad around 50k.

TimC300

I replaced my front links because they were making a clunking noise going over bumps on the highway. They would clunk 3-4 times in a row, like they were bouncing. The boots were torn and leaking grease out. With both front wheels off the ground i was able to grab the links and rotate them easily, if you do it quick enough you will hear them make the clunk noise. When i removed them the ball and socket would just flop around they were so worn. probably due to age and water getting in washing the grease out.

i bought replacements from FCP Euro for the lifetime warranty. Certain wear items like the links, brake pads, rotors ill pay the little extra for the warranty. The warranty is ok but its not like they give you your money back, if the part fails you have to buy the same exact part, pay to ship them the used part then they give you a gift card for the original price you paid for the 1st part. So your stuck with a gift card. To use it means something else has broken on your car.

I was just under my car yesterday inspecting things. With the nice weather finally here i like to pull the wheels and check everything over, clean off all the brake dust and squirt some silicone lubricant on all the bushings and rubber boots. Grab hold of the control arms and give them a good tug to check for any movement. I noticed a little bit of grease being flung around which I think is coming from a tear in the cv boot so ill have to figure that out.

Just204

that’s a very small amount of grease. I wouldn’t worry too much right now, I’d make a note of it and plan to do it when a good time comes. I’ve rebuilt mine a couple times now. Looks like it’s the passenger side, lucky as it’s the easy one to do.

TimC300

it looks like a small tear but its flinging grease everywhere. Im thinking for now i'll get one of those needle attachments for my grease gun and carefully pump some new grease in thru the tear. i only have the red and tacky grease so have to figure out what this black grease is.

Just204

you can buy the specific grease you need on fcp euro.com . I’d buy that and put some in but don’t overdo it as that will put extra pressure on the boot. Are you in NY. I’ve rebuilt several MB axles.

TimC300

Im in MA. i did a little searching to see if pumping grease in is a good idea and seems it may not be. Something about if theres too much grease it can heat up then blow the boots out even more. i just received a needle adapter for my grease gun, maybe ill give it a go. i just have the red and tacky and see i need specifc axle grease.

I wouldnt mind just replacing the boot if its easy enough. i also found a used Mercedes axle on ebay for around $100. Maybe ill get that and see if i can rebuild it, practice on it.

Just204

if the axle isn’t making a clicking sound it’s still good, mine were much worse when I rebuilt them and theyr fine. If it’s an OEM axle just buy that and hope it’s good, replacing boots is a bit messy and takes a bit of time to do. But not too long 1/2 hr max plus taking it out and putting back in.

TimC300

Im just wondering how the axle is held together. Meaning are there clips holding the sections together, or when i cut the clamps on the boots will the sections just pull right apart? I know there is a clip that holds the three bearings on the shaft that has to be removed to fit the new boot on.



Surprisingly my axle looks newer to me, can easily read the sticker. Im thinking if it were the original axle it would be trashed by now.

Just204

the inside and outside cv joints are different, the inner slides in and out while the outside pivots. The outside is held together with a pressure clip(or whatever it’s called). To separate the outside cut/remove the boot. Put the shaft in a vise, take a 2x4 and put it against the inside of the cv joint and keep it straight, then take a heavy hammer and wack the 2x4, that will pop it off the clip and separate the joint from axle. Clean real good, slide the inner clamp onto the shaft, put the boot on, put the boot in place on the shaft and clamp the band clamp on, make sure the cv socket is straight and place on the shaft, hit it on with a dead blow, fill the boot with grease and clamp on the outside band clamp. This is it in a nutshell. It’s a little different for the inside boot.

jetson

Well I replaced the sway bar links and it did not fix the noise. There does not seem to be a clunk but more of a creaking from driver side front. Jacked the car up and put ramps under wheels. While laying on my back pushing up on front end the noise goes away but when car settles it comes back. I put my ear to the strut top and noise does not seem to be coming from there. However when putting my hand on front forward control arm (big curved one) you can feel it. So I replaced it last night. What a PITA. Felt good about myself when done BUT there was no change in the creaking when turning or articulating over bump.. Any ideas on where to look next? Would a motor mount cause this?

JettaRed

iTrader: (1)

Try lubricating all rubber bushings, etc. with some silicone spray. If that works, then you know that it's a bushing that is old and dry. Did the clunking go away? You may have bad strut mounts.

TimC300

The creak could be coming from the sway bar bushing, where it attaches to the subframe. Try squirting some silicone lube on all the bushings , even on the rubber boots of the ball joints for good measure. Silicone lube wont hurt the rubber. Do not use oil, it will eat the rubber.

jetson

Going to try the silicone and see if I can narrow it down. As far as the strut mount. I don't have a spring compressor and some of the ones you can get look very sketchy. Does anyone have any experience with buying the complete strut with the coil. RockAuto has one for $85.....FCS? Has a limited lifetime warranty.

TimC300

When one of my front springs broke i didnt want to deal with having just the spring replaced so i bought a low mileage used set of Mercedes struts and swapped them out. Im pretty sure they were the original struts with 150,000 miles on them so i felt comfortable putting a used 40,000 mile set in there.

I have no experience with aftermarket front struts. I looked up FCS and found them on eEuroparts which I buy things from. Says it has a 2yr warranty on the strut failing.

But are your struts really bad/worn? My spring was broken so obviously needed replacing. Not sure id replace it just based on a creaking noise. Currently im having a creaking noise from my passenger side, which I remember having before and it went away.

TimC300

I did some searching for FCS reviews, also TRQ reviews since I keep seeing TRQ front strut ads.

My concern would be ride height and spring rate. When I look at the fitment for the FCS it lists them working with all W204's, sport and luxury. But the springs for the sport and the luxury are different part #'s from Mercedes. In my 4matic sport the springs have 2 yellow dots and 1 white dot on them. The luxury springs have something like 3 red dots on them.

I mention this because when I was ordering replacement struts before i ordered one off ebay that was listed at fitting a 4matic sport, but what I received was the strut with 3 red dots. When i installed it the ride height was at least 1/2 taller on that side. It looked jacked up so I returned it.

So while it did fit it was not the correct one the car originally came with.

jetson

Well I sprayed everything this evening. The sway bar bushings, lower control arm and tie rod. No change in the noise. Here is what is sounds like.

TimC300

That sounds like a clunk to me. Like metal on metal.

loose wheel bolts comes to mind hearing that. Not saying thats what it is, just what I picture it sounding like.

Have you checked all the suspension parts at the wheel carriers? Bal joints.

TimC300

With the front end jacked up use a rubber mallet and start wacking things, see if anything is loose, or sounds off.

jetson

I am running out of things to check. It does sound like a clunk from that post but more creaky (metal on metal) sound in person. I have greased, hammered, and used a pry bar on everything to no avail!. The lug bolts have been torqued. The tie rod ends feel tigh as well as the control arms. I guess I will try replacing the strut mount and bearing. I don't think the sound is coming from there but I don't what else to do?

TimC300

Have you tried jacking one side up, remove the wheel, then use another floor jack under the wheel carrier and jack it up and down? May be able to see or hear something making noise. When i did this i could hear a creaking up top of the strut, i just sprayed a bunch of silocone lube everywhere, pulled the dust boot down and squirted some in there. Not sure it really did anything but the creak did go away. Im actually now hearing a creak again, a year later so im about to go inspect everything.

have you inspected the springs and the shims? Are the struts leaking? When my spring broke it was right at the bottom, if i wasn't so **** I maybe wouldn't have noticed it was sitting slightly lower, but the car was still able to drive fine for the few days while i got new struts ordered.