My 1985 Mercedes 300D shudders at high speed, about 90 mph. I rarely drive faster than 65 since I'm over 40 now, but the other day I came to the aid of someone in a bad situation and had to drive at very high speed.

The shuddering reminded me of my teenage days when i tried to get high performance out of tiny imports and at high speed they werent too stable.

I know I wont have to drive at 90 mph that much, but shaking does make me wonder and I want to fix it.





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Has the front suspension ever been rebuilt? That's probably at least part of the problem. What kind of tires? Are they worn unevenly from poor alignment?

Mike

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1979 300 SD
350,000 miles
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1982 300D-gone---sold to a buddy
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1985 300TD
270,000 miles
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1994 E320
not my favorite, but the wife wanted it

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It is my experience that shaking above 80+ is always tire balance related. Often, if you observe closely you can see it in the dash and steering wheel if it is the fronts.

Rear balance problems sometimes can be observed in the interior review mirror and seat backs bouncing.

If you don't experience this other than high-speeds, tire balance is where I'd start. Make sure you go to a place that has a newer balancing machine.

I just noticed that we are getting a shimmey in the steering wheel of the 190E at around 45 mph only after going over a bump. I suspect it is a worn steering damper.

Keep us updated on what you found.

Haasman

__________________
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)

maybe it's afaraid of cops.........
William Rogers......

As haasman said, it is almost certainly wheel balance. Loose suspension parts and the like don't MAKE vibration, but they will cause it to be more pronounced.

The biggest problems I've had with 123 cars over the years is getting the tire store kid to balance them correctly. They insist on using weights ONLY on the inboard wheel lip because people complain about wheels being scratched by the weights or they say the weights are ugly. It is always a fight for me to get them to do it right with weights both inboard AND outboard.

I finally gave up and bought my own wheel balancer.

If there are no weights on the outboard lip, find someone that will DYNAMICALLY balance the wheels with weights on both planes. Don't let them feed you any bull about inboard weights being just as good, that is B-!! $#!+.

Good luck,

mr. bible, are you using a bubble balancer?

hasnt been rebuilt. But what can you really rebuild, except the ball joints and the shocks? The front end was aligned by a very good guy....

I do most of my work, except alignment and welding. I will do even the Ball Joints. I'm glad Mr. Bible told me he bought a Balancer---now I wont feel guilty for buying a Pitman Arm Puller next week. We have to watch out, the moderator edits these posts for b.s., but sometimes I wonder what the craziest tool someone has bought is.....

The suspension's idler arm bearings also contribute to a shimmy, but still I think if it is speed related, it is wheel balance.

I replaced the track-link on our 300E and that definitely firmed up the steering.

__________________
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)

janko,

I got so frustrated with the tire stores that I bought a used Coats 1001 computer balancer. It does a spin, dynamic balance. Static balance can be done on a bubble balancer, that's all. The Coats can do a static balance but I won't bother, only dynamic with weights inboard AND outboard. I always check static after dynamic because they interact.

Static balance prevents the wheel from hopping up and down, while dynamic keeps the wheel from wobbling. The wobbling is felt through modern suspensions.

Carrameow,

Yes the idler arm can allow a shimmy condition, but most all vibrations are caused by poor wheel balance or a tire with excessive road force variation (stiff spot.) Loose suspension components will AMPLIFY vibration, but very rarely CAUSE the vibration.

If you were here, I would give you a 95% chance of my balancing those wheels correctly and making the vibration disappear.

Good luck,