On my usual 32 mile commute on highway at about 65-70 mph, suddenly the front end started shaking violently. Not a mild shimmy but a steering wheel grabbing, car shaking, scare driver thing. Dropped speed to change lanes and go to shoulder--somewhere around 45-50 mph the shaking stopped. I pulled over and looked around. All looked same as usual.

The only front end work I have done is to replace the guide rod mounts and all looked normal there. The tie rods need replacing and will be done soon--maybe this weekend.

I decided to ease on to the office and did so, staying at 50 mph or below. All smooth.

Any guesses?

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1984 300SD 326,997 miles and counting . . . No wait, my odometer is still dead

A wheel weight fell off.

JCD

I see by you photo that you have the 14 inch rims so that rules them out. A missing lug bolt on the newer rims will cause that. It is possible you threw a weight, but unless you have such crappy tires that require 6 or 7 ounces on each tire, I don't think that is the problem. I think you are experiencing tire separation. You will need to jack up each end of the cay starting with the front and rotate each tire slowly and watching carefully for bulges. Of course check all steering components while the front end is up.

Peter

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Auto Zentral Ltd.

An after thought. Have you driven the car at highway speeds since replacing the rods or is this your first time out? Not adjusting those rod correctly could give you negative castor which could also allow steering wander.

Peter

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Auto Zentral Ltd.

I just had this exact problem last week. It's very scary, I thought a wheel was about to fall off. I had just come over a rise at about 70 mph, and was on my way down when the vibration started. It had happened once before under similar circumstances. I replaced both tie rods and the idler arm/bushings, and the problem went away.

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Tjohn

82 300 SD
77 450 SL (gone)

Check the steering stabilizer, the horizontal "shock." Just drop a bolt form one end and see if it has any compression. My SD does the same thing from time-to-time and the stabilizer is original at 240k (on a long list of replacement items).

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Rick
Avid Benz watcher

Previously owned 126's: 2 1981 300SD's, 1987 300SDL, 1991 350SDL,
Previously owned 123's: 1978 300D, 1983 240D, 1985 300D
Previously owned 124: 1994 320TE

Currently:
2004 Toyota Sequoia SR5 206k
2010 Ford Edge 122k
Always looking for the next MB diesel!

Yes everyday for a total of over 1000 miles since guide rod change out. No steering wander before or after this episode.

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1984 300SD 326,997 miles and counting . . . No wait, my odometer is still dead

Thanks, it is on the list of things to check and replace if needed. How bad is your shaking when it happens to you from time to time? Mine was serious and bordering on loss of control when this happened.

I will also check the tires and wheel weights but these are good Michelin tires and this was much more than an unbalanced tire should cause. I have caked pounds of mud inside wheels on my Jeeps and Land Cruisers throwing balance off and getting some wheel shaking at speed but nothing like this.

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1984 300SD 326,997 miles and counting . . . No wait, my odometer is still dead

It is more like an out-of-balance wheel, not real bad. It is intermittent and is usually worse when I hit bumps/holes at about 65-70 mph. It has only been the "violent" type for just a second once and I backed-off quickly when it happened.

I recognized the symptoms from my dad's '66 3/4 ton International pickup of a few years ago. I used to just speed up to make it quit! The SD has quit with speed increase too but it's just not safe. I'm only using the SD for short hops around town right now.

I plan to sell the 240D and totally restore the SD.

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Rick
Avid Benz watcher

Previously owned 126's: 2 1981 300SD's, 1987 300SDL, 1991 350SDL,
Previously owned 123's: 1978 300D, 1983 240D, 1985 300D
Previously owned 124: 1994 320TE

Currently:
2004 Toyota Sequoia SR5 206k
2010 Ford Edge 122k
Always looking for the next MB diesel!

I had the tread separate on a set of 2 year old Michelins, such that I thought my right rear half shaft had gone bad.

Your suspension issues probably made the vibration more violent, but I would doubt that they are the root cause.

I would first check the tire, the wheel weights, balancing, lug nuts, etc.

JCD

Yeah, I agree. Something has suddenly changed. The tie rod ends are not tight like new, but not that bad either. Steering stabilizer is of unknown age and condition, but not likely to cause this sudden problem either.

Looks like I get to spend some quality time this weekend.

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1984 300SD 326,997 miles and counting . . . No wait, my odometer is still dead

Rockin,

Ok guide rods not the problem, so I'm saying you may be experiencing what JCD experienced. After 30 years experience as a factory trained MB mechanic I have a hard time believing any badly worn front end component could cause what you experienced unless you have something coming loose. Let us know what you find.

Peter

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Auto Zentral Ltd.

Well, since I had just replaced those guide rod mounts, I thought maybe one of the housings had come loose from the frame but no, those appear good and tight.

Will post as soon as I know anything. I need to get home this afternoon. Should be no big problem unless something really comes loose. Slow traffic on Friday afternoons is a given around here. Just for fun, I'll double check the lug bolts and tires before I take off.

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1984 300SD 326,997 miles and counting . . . No wait, my odometer is still dead

- The tires on the inside. I had a tire deform on the inside and it started rubbing on the tie rod end. Make sure there's no rub marks on the tie rod or tire.

- Wheel balance. Always seems to be the problem for me when I get vibrating.

- Tie rods. I'm guessing that this is the problem. When the vibrating occurs on the highway, do a slight but QUICK left then right turn of the steering wheel. If it helps to stop the vibration for awhile it's probably the tie rods.

Another way to check the tie rods is to jack up the front end of the car. Grab the left and right sides of the tire with your hands, and then alternately push your left hand in while pulling your right hand out, and vice versa. If there is any movement it's probably the tie rods.

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1980 300D
1977 450SEL

Steering stabilizer. We get them often. They are cheap and easy to replace. Gives ya one hell of a shimmy.