126 rumbles - front end rebuild just done

[benzboy87]

1990 420SEL - I just had the front end rebuilt and this rumble was there before and is still there. When I am at highway speeds above 60 the left front rumbles and vibrates somewhat when curving to the right. This was there before I had the front end rebuilt. It has been aligned after the rebuild. It is not a bad wheel bearing or it would do this all the time.
Could it be something as simple as rotating the tires? The driver's front tire is somewhat worn on the outside edge - hence the rebuild. I plan on having them rotated tomorrow. Any ideas? (First thing I did was check tire pressure to make sure it was not low.)

[Palangi]

I dunno much about the V8's and the newer cars, but on an old diesel, you can get a rumble while turning or while decellerating due to worn engine mounts. I think the mounts bottom out and transmit the engine vibration to the frame.

[MikeTangas]

Did the rebuild include ball joints? My 560 had a rumbling knock, which originated from the badly worn ball joint that only occured during right hand curves.

[benzboy87]

Mike, I think you are on to something. I had the motor mounts changed while all this was being done but did not have ball joints replaced - the tech said I did not need them - but she could be wrong. I only get this when going over 60 and in right hand curves - same as with your 560.

[Jim H]

Originally Posted by benzboy87

...Could it be something as simple as rotating the tires?

Yes. Worn tires can rumble. A lot. Don't ask how I know...

[sbourg]

I agree, tires are often the culprit, particularly if worn oddly by previous front-end troubles. Usually an easy diagnosis, simply rotating front-to-back. Last time I had this problem, noise did not go away, but resurfaced at the back. Sometimes, though, it will cure the problem AND salvage use from the offending tire.

Steve

[MikeTangas]

I still think the left lower ball joint is had it. The key is his initial description about rumbling when curving right at highway speed. As the ball joint deteriorates the first perception is a very minor shimmy during this manuever, then the steering wheel begins to visibly move followed soon by a low rumble. If left unattended it will develope into a rumble with an almost harmonic knock.

When mine started I thought I needed an alignment, but since the tires were wearing pretty even I let it ride. When the rumble started I did the front end rebuild, everything except the LCA bushings.

[benzboy87]

Took the car today to have tires balanced and rotated. Have not had a chance to drive it on the interstate yet but it sure handles and drives a whole lot better. The guy who balanced it - same place I bought the tires over a year ago - said whoever installed them did not balance them to begin with! I stood over him while he did the work (just for my own piece of mind) and there were no wheel weights until he added them. He also torqued all the wheel bolts by hand without even having me suggest it. I could tell then he had worked on MBs before! I will make sure he does the next set of tires I purchase!
I will try to get out to the interstate this evening to see how it does.