Low Rumble or vabration after 40 mph W124

[roehlerich]

Hi all,

I just joined. I just purchased a 89 300ce with 107k miles. I just replaced the front struts and still need some new tires, since one of them was wearing really bad on the inside. Last owner did "nothing" for 3 years or 4k miles.

This issue I have is that I have a low rumble/vibration when I push the gas after about 40 mph. I take my foot off the gas, the car cruises fine. This does not go away at higher speeds. Uphill or under more load is gets worse. Never to the point that I am alarmed, just want to know what this might be.

Thanks in advance for any advice. I am in Norristown, PA and would like to know of other MB owners in the area. I do a lot of car work myself and am looking for likeminded people in my area.

Thanks,

Ralf

[ozzy]

Replace the tyres.

[dpetryk]

Check the following;

Drive shaft, drive shaft center bearing, flex joints, rear wheel bearings.

[archibald2]

thought I would chime in on the subject as my '95 W124 wagon has had the same low frequency thromb (I made that word up) resonance for a few years. I have had the tires replaced, balanced, rotated, & now that I live in Canada installed another set of tires (winter) on an entirely different set of wheels. None of these changes had an effect on the low frequency vibration or resonance that occurs between 40 & 70 mph. I too am stumped. My indie is going to pull the shaft in a couple of weeks and send it to a shop and see if it is balance. The only other change might be the u-joint between the two shaft segments.
I am curious to know how you make out.

[dpetryk]

I had the same problem on my 86 300E. It turned out that there was a dampener of sorts on the transmission end of the drive shaft. That thing consisted of a rubber coupled steel ring assembly mounted on the end of the drive shaft. Well needless to say the old rubber gave way causing the shaft to be out of balance. That caused high vibration forces which over time ruined the drive shaft coupling where it stabs into the alignment pin in the back of the transmission. I ended up replacing the drive shaft to solve the problem and I was not able to replace the dampener since BM did not sell that thing separately.

[Ferdman]

Ralf, as already mentioned I would inspect the condition of the flex discs (one at transmission, one at differential). Replacing the flex disc(s) is a DIY job with the right tools and patience. If you're unfamiliar with them it would be best to have an independent MB-trained tech inspect the drive train so as to avoid further damage.

[troylatif]

Interesting. I just rebuilt my 280e motor. In the process I pulled the tranny and therefore the driveshaft. I also get a bit of a vibration through the body at higher speeds.

The flex discs looked okay to the naked eye. Could reinstalling the driveshaft in a different than previous position cause some sort of imbalance due to placement or does it not matter with flex discs?

-Troy

[Ferdman]

Troy, the driveshaft halves are match-marked so it's important to reinstall them in the same orientation so the driveshaft remains balanced. When I replaced the rear flex disc in our 1992 300CE I made sure to maintain the same orientation with the drive shaft and the differential, although I doubt that it matters. I did not separate the driveshaft halves.

[Roger Jones]

I'd agree with all the suggestions above. Then consider what the E-class owner's bible says:

"All E-class

Rumbling/humming in speed range from 110--150 kph.

Driveshaft out of balance. Balance driveshaft. If problem persists, install rear differential vibration damper (124 350 03 72) at rear subframe. Tightening torque 150 Nm."

My mechanic reckons an out-of-balance driveshaft is very distinctive and therefore easy to diagnose. In the case of my E320 Coupé we fitted the damper -- a heavy lump of easily fitted metal -- which had some effect but has not eliminated the problem entirely. Now I have a centre bearing to replace.