98 E320 mystery front end noise with new clue - PeachParts Mercedes-Benz Forum

nckmsn · #1 10-23-2010, 01:02 AM

For sometime I have been unable to locate the source of my front end noise. The best way to describe it is a clunking noise as though something is loose in the front end. I have checked for play in everything but haven't found the source.

I have noticed that the sounds happens more often on rough roads and when going over a manhole or something similiar.

The clue new clue is that I changed the front end shocks today and the noise got much worse. Can anyone guide me? I would think that I would easily see play in the front end with such a pronounced noise. I think that the fact that new more responsive shock has made the sound louder should point someone in the right direction.

Thanks in advance for any help

mbzman · #2 10-23-2010, 01:16 AM

Have you inspected the strut mounts?

nckmsn · #3 10-23-2010, 11:34 AM

If by strut mount you are talking about the spring perch, then i have inspected them.

Is there something else I should be checking. I also inspected where the shocks mount on the top and bottom.

Thanks for your help

benzs500 · #4 10-23-2010, 12:43 PM

I am having a very similar problem on my 2000 E320. I took it to a suspension place near my city today and they told me they could not find anything wrong. I am going to look at it myself this weekend and take it to another place I know on Tuesday. It only does this at lower speeds over multiple or choppy bumps. Sounds likes something is loose. Car rides excellent other than that.

I'll post anything I seem to find out.

nckmsn · #5 10-23-2010, 12:48 PM

I am leaning towards sway bar bushings making the noise. Mine look like they are getting old. Anyone have an idea if this may be the culprit?

Benzs500- Your problem is identical to mine from what I can tell. I'm sure someone will help us out.

mpolli · #6 10-23-2010, 03:05 PM

When my sway bar bushings got worn they would squeak when I went over a speed bump. They didn't clunk. But mine is the C not the E

gregs210 · #7 10-23-2010, 03:11 PM

Excellent information, gents.

It's either the sway bar bushings or the sway bar end links.

Since both are inexpensive and easier to change if you do them together, that would be my recommendation, and it is suggested to do both sides at the same time. (Replacing only one will increase load on the other and they do wear together.)

This is also a good/simple DIY job. Parts are readily available and about $50 - total - if you shop around. Some places offer free shipping if you spend like fifty or $75, so toss in an oil or air filter if you're close.

benzs500 · #8 10-23-2010, 05:15 PM

My guess is the same. I had a Volvo S60 make the same noise and it was the swaybar/swaybar bushings.

Any clue why the mechanic I took it to today couldn't diagnosis this? My guess is that they were either lazy and didn't look close enough, or just aren't that familiar with MB.

Either way hopefully this will solve our problem...

gregs210 · #9 10-23-2010, 05:52 PM

Quote:

Originally Posted by Benzs500

Any clue why the mechanic I took it to today couldn't diagnosis this? My guess is that they were either lazy and didn't look close enough, or just aren't that familiar with MB.

Either way hopefully this will solve our problem...

One of the three, or perhaps a combination.

But it is more diffficult to diagnose, just sitting in a shop on a rack, as the sway bar has to be in a load-transition posture to release pressure on the links, which then rattle. One mechanic can simply drive it and tell, whereas another might tinker with it on the rack and find nothing.

Railroad tracks are ideal for the test, particularly if you can safely side-load a bit going over them (quick lane change for example while the front tires cross them). The way to distinguish is that worn bushings are more likely to be a deeper sound, perhaps a sort of clunking, that can often be felt through the front floorboard; end links are a little lighter in tone and frequency, sometimes described as a rattle. However, just changing the bushings will sometimes then isolate the end links and they start making noise. Same thing with changing the shocks; that stiffened things up and displayed the "weak link".

That's why I suggest changing them together, not to mention that when you change them at the same time it takes pressure off of each, making the whole job easier. It's only 8 fasteners total IIRC.

None of these parts affects alignment, so this is a great way to get a little dirty, gain some satisfaction in a DIY job, and save a good chunk of change. Parts at retail/plus, shop charges and labor, you could drop $350 at the stealer, not to mention the time wasted going there. Of course you won't get their "free" coffee or "complimentary" car wash.

RPM55 · #10 10-24-2010, 04:15 PM

Have you checked the lower ball joints? With the car on a lift or on jack stands with the front tires off the ground squeeze the lower ball joints with large water pump pliers, there should be no play.
The other possibility is the sway bar links, but not as common as worn ball joints.

Good luck,Robert.

benzs500 · #11 11-24-2010, 12:56 PM

Finally found out on my car it was the swaybar links and the control arm bushings. Replaced those and the noise is gone! Not too expensive of parts, but I had to take it to a friend that has a lift to do. This was a little more than a home garage job. Just thought I would update. Thanks!