83 300SD has redeveloped a very disturbing shimmy at speeds over 60.
Only occurs if I am in a corner and hit bumps in the pavement.
Shakes like a dog passing a peach pit....
Feels like the front tires are wobbling back and forth more than up and down, although I haven't been able to visually confirm this feeling.
Only way to stop the shake is decrease speed.

This problem originally appeared after putting new wheels and tires on the car, and then went away after I got the tires balanced and an alignment done...
At that time I also put a 1/4 turn in the steering box.

The tie rod ends are both good, and I can find no slop or play in the suspension.

Anyone ever have a similar experience with one of these w126's?

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On some nights I still believe that a car with the fuel gauge on empty can run about fifty more miles if you have the right music very loud on the radio. - HST

1983 300SD - 305000
1984 Toyota Landcruiser - 190000
1994 GMC Jimmy - 203000

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I've not experienced this in a W126 but I'd be checking for any evidence of a missing wheel weight - might have fallen off

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Sounds like worn/damaged front end/alignment issues.

Considering your mileage and age, you may be getting a cumulative stackup in wear, allowing the shimmy.

I don't believe it's a balance problem, that would be there all the time, regardless of road surface or cornering.

I've had this problem on a couple of cars, and in both cases, the front end was pretty shot.

Also, if your new wheels have a different offset than the originals, and the line drawn through the steering knuckles no longer intersects with the center of the tire contact surface, that can exagerate the problem of worn components. E.G; If the center of the tread is now outside the line thru the axes, a bump or force on the tire/wheel will increase the deflection force of the bump. Another way to visualize this is to imagine a rod that you hold at the center of the length. If you attempt to push on the rod at your hand it is hard to deflect the rod, you can only push it back. However, if you move a bit to either side and push, you now can easily deflect one side of the rod, adding a twisting motion as well as the intial force vector pushing straight back.

Jim

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14 E250 BlueTEC black. 45k miles
95 E320 Cabriolet Emerald green 66k miles
94 E320 Cabriolet Emerald green 152k miles
85 300TD 4 spd man, euro bumpers and lights, 15" Pentas dark blue 274k miles

For that much shimmy, I would suspect ball joints first, especially the lower ones.

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Sam

84 300SD 350K+ miles ( Blue Belle )

I had the same thing happen on my first 300SD. I replaced the tie rods and link and never had the problem again.

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1991 F250 super-cab 7.3 IDI. (rebuilt by me) Banks Sidewinder turbo, hydroboost brakes, new IP and injectors.
2003 S430 - 107K
1983 300SD - Tanoshii - mostly restored ~400K+.
1983 300SD - Good interior. Engine finally tamed ~250K.
Monark Nozzle Install Video - http://tinyurl.com/ptd2tge

The front end in this car is completely shot.

Parting out Mercedes Benz 1990 300SE drive test - YouTube

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1991 F250 super-cab 7.3 IDI. (rebuilt by me) Banks Sidewinder turbo, hydroboost brakes, new IP and injectors.
2003 S430 - 107K
1983 300SD - Tanoshii - mostly restored ~400K+.
1983 300SD - Good interior. Engine finally tamed ~250K.
Monark Nozzle Install Video - http://tinyurl.com/ptd2tge

Stock wheels? I had this problem with 18" wheels and never figured out what it was.

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1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

I suspect that Jim is on the mark, although nothing feels loose when I have it in the air... Of course, things get a lot different with the weight of the car and the speed...

Winmutt, I put on 16" AMG replica wheels. At least I think they are replicas... they say they were made in Italy. And they do have a different (further outboard) offset.

I think I will try another steering box adjustment, and then start gathering some pieces for the front end.. Of course, the car is getting pretty well used up, so I really don't want to put a ton of money into it that would be better spent on a less used up example of these vehicles.

__________________
On some nights I still believe that a car with the fuel gauge on empty can run about fifty more miles if you have the right music very loud on the radio. - HST

1983 300SD - 305000
1984 Toyota Landcruiser - 190000
1994 GMC Jimmy - 203000

https://media.giphy.com/media/X3nnss8PAj5aU/giphy.gif