'89 420 sel with 185k

i have been rebuilding most of the front end in recent months in part because it is 20 years old and to finally get rid of all the squeaks and groans...

below is a list of everything i have replaced to date (i think this is everything...). the problem is that i still have a rumbling noise in the front end at lower speeds when traveling over any bumps ranging from the lip of concrete on my driveway apron to railroad tracks. anytime i am driving over an uneven road, it rumbles constantly. i don't notice it at higher speeds but the highways are in pretty good shape.

any suggestions would be appreciated.

Upper control arm
Steering knuckle (lower ball joint)
Guide rods
Guide rod mounts
Tie rods
Spring shims
Engine mounts
Transmission mount
Eccentric pin kit
Idler arm
Steering damper
Sway bar bushings
Lower control arm bushings
Front and rear Shocks (about 4 years ago)
Engine shocks (about 5 years ago)
Repacked front wheel bearings
New Michelin mxv4 plus tires (front end alignment)
Subframe bushings
Suspension brng brkt

Rumbling sounds like wheel bearings to me.

Tom W

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Squeaks and rattles are very hard to diagnose. In your case the rumble happens at very low speed, this makes it easier. I would advise to have someone standing near the lip on your driveway when you drive over it and try to find out where it comes form. The driver should concentrate on driving so the listener does not get run over.

If that does not work you can try to find a shop that does shock testing with vibrating plates under the wheels.

Possible causes for this rumbling are:
-Hood alignment / vertical adusment screws
-Lose front fender
-Fan hitting the radiator shield
-Battery not properly secured
-Air filter housing
etc
Rob

Tom,

I had the bearings repacked and have since checked to see if there is any movement in the wheel itself while it is in the air - nothing seems amiss. Any other suggestions as to how I might check them?

Thanks.

If the noise goes away at higher speeds, then its probably not a bad wheel bearing.

As an aside, I had a wheel bearing that seemed OK but rumbled like crazy. On closer inspection, I found a tiny nick on the surface of one of the races. That little flaw can make a real big noise.

__________________
1985 380SE Blue/Blue - 230,000 miles
2012 Subaru Forester 5-speed
2005 Toyota Sienna
2004 Chrysler Sebring convertible
1999 Toyota Tacoma

As I listed earlier, I recently replaced the motor mounts and the spring shims on the front end of the car. As I have been looking at the front end over the past few days, it now looks to me like it is jacked up... The fender is approximately 4.5" above the tire - is this a normal height? The spring shims were only about a 1/4" difference in thickness (old to new) and I don't think the motor mounts would cause any change in height...

Yeah, 4.5 inches sounds like a lot of fender clearance.
When the wife gets home I can check mine.
But, a 0.25 increase in shim ht on the spring can make a much bigger difference in the ride ht of the car, due to the leverage effect of the
control arm. I went up one size on the rear of my car, and I swear it raised the rear over an inch.
I looked up the std spring shims for the 126 that are used, depending on engine, equipment, weight, etc.
8mm = .32"
13mm = .52"
18mm = .72
23mm = .92
Yours probably came with the 13 or the 18 (being in between the lighter 300SE and the heavier 500S).

But, all things being proper, a change in ride ht should not create a rumbling noise.

DG

I measured my 300SE - 27 inches to the edge of the fender well above the middle of the wheel.
See the thread below (if I did this right.)

1989 420SEL ride height?

DG