FYI.

I had been hearing a 'rattle' at low speed in my 300SD
coming from the front left. It sounded like ball worn
ball joints.

I had it diagnosed at a dealer - it was the two torsion rods for about 48.50 each, plus diagnostic time and
a 4-wheel alignment.

My car has 165,000 on it. I understand from the
service department that this replacement sounds about
right for the w140s.

Feels and sounds like a new car again! :-)

I hope this helps somebody who is getting strange sounds
from under the hood.

-Ralph
1993 300SD

many many thanks for the info. I'm having the same situation at this time. When I push down the front left corner of the hood, ...I can hear a rattling sound, ..I suspect that it is the guide mount bushing that is failing.
Where is the torsion rods located ? Could you please expand this info some more........Will the front springs or shock absorbers create this same rattling sounds..?

My shock absorbers were replaced at about 120,000 miles
because one was leaking.

At first I thought that my lower ball joints were going.
I had a rattle at low speeds over bumps as though some-
thing was loose. Hitting bumps, etc. at highway speeds
was no problem.

I had previously put new wheels and tires on the car. The
mechanic looked at the ball joints and, finding that the
rubber boots, etc. where not cracked, that they were
problably ok.

I had the front-end work done at a dealer who also does
the 4-wheel alignments in-house. They are finding that
W140 body cars with 150,000+ miles on them are wearing out
the torsion rods (two of them). It must be pretty prevalent
as I got the following work done in one day:

1. diagnosis of my front end.
(with 2 or 3 times on the road)
2. a 4-wheel alignment.
3. an oil change.
4. transmission service.
5. front tires rebalanced.
(I know, I just had new ones put on)

When driving the car, the rattle seemed to come from the
left front near the wheel. I guess that I could not hear
the right one.

Also, the steering was solid and the car did NOT want
to drift on the highway - apparently another sign of
worn ball joints.

I doubt that the springs or the shocks would produce the
same sound. In my case, I wasn't sure what it was. That
is why I took it to the dealer. I was also concerned that
I would do more damage if I continued to drive the car
without the problem being fixed. I also just put 4 new
Michelins on and I didn't want to ruin them.

I am a fan of independents but unless the mechanic
knows front ends and has had a fair amount of experience
with the w140 (or perhaps the w126) I am inclined to
opt for the dealer. If you know of an superb front-end
shop that does a lot of work on Mercedes, that might be
an option. The diagnostic work costs a lot more than the
parts (about $90) so going to someone with a lot of
experience with the car seems to make sense.