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Discussion Starter #1
The car is in almost perfect condition.

Almost.

A vibration is plaguing the driving experience. Between 60 and 75mph the vibration is most pronounced, but it rears its ugly face at other speeds as well.

Sometimes the vibration seems to (briefly) go away entirely, while other times it's really bad.

When acceleration hard above 70mph it likes to rear its head, but also when coasting or maintaining speed. It's not dependent on engine speed.

I feel it on the throttle pedal and see it on the passenger headrest.

I don't feel the vibration in the steering wheel at all.

The back tires are new contis, the front tires are older somethings.

I've had 3 balances done, and had a wheel "straightened". I've also done an alignment. I've also replaced the rear flex disk. The disease persists.

Googling yields so many forum posts describing exactly this: vibration at 70mph seen in the passenger headrest, and inevitably everyone suggests everything, and OP invariably tries everything, but rarely does something helpful come out.


WHY IS MY CAR VIBRATING?!?!?!!??!!!
 

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as I said at mbworld :
Engine mounts , Tranny mounts , wheels and tires . It's one of those but we don't know which .

I like to tackle these in terms of least cost - if you gave another set of wheels or a friend with the same car , first swap tires and wheels , recheck . $20
If you don't have access to another set , rotate your tires and wheels , $20.
Or go to a custom wheel shop that deals in a lot of mb and see if they have an extra set

Not fixed? change tranny mount , $100

Not fixed ? Change engine mounts .
 

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Discussion Starter #5
as I said at mbworld :
Engine mounts , Tranny mounts , wheels and tires . It's one of those but we don't know which .

I like to tackle these in terms of least cost - if you gave another set of wheels or a friend with the same car , first swap tires and wheels , recheck . $20
If you don't have access to another set , rotate your tires and wheels , $20.
Or go to a custom wheel shop that deals in a lot of mb and see if they have an extra set

Not fixed? change tranny mount , $100

Not fixed ? Change engine mounts .
Already changed the transmission and engine mounts. I've considered temporarily switching the front and rear wheels to see if the characteristics of the vibration changes.
 

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Discussion Starter #7
I know the part. It's $30 for Vaico, and $120 for OEM mercedes from ECS.

Is there an easy way to test this part? Feel the drive shaft for play? I don't feel any vibration in the shifter where I would expect to feel something.

Another part I've considered checking is the differential bushings.
 

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I know the part. It's $30 for Vaico, and $120 for OEM mercedes from ECS.

Is there an easy way to test this part? Feel the drive shaft for play? I don't feel any vibration in the shifter where I would expect to feel something.

Another part I've considered checking is the differential bushings.
There will be a small amount of movement in the rubber but the bearing should have none. Hop under there and give it a good wobble and see how much movement it has.
 

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I have a 2000 W202. I also had problems with vibrations at highway speeds. For years I took it to a local Firestone dealer who sold me a lifetime alignment. I was never satisfied.

Eventually an employee at Firestone informed me of Mercedes' use of eccentric bolts and washers for alignment of their cars. It is a process only the dealerships are truly prepared for.

I have since begin taking my car to the local dealership for alignments, and have been happy ever since. No more vibrations at highway speeds.
 

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search my nick on both forums for my comments on the forward mounts of the rear axle suspension table. The forward ones are hard to inspect, and if gone allow the diff to shift up and down with accell/decell.
 

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Discussion Starter #11
search my nick on both forums for my comments on the forward mounts of the rear axle suspension table. The forward ones are hard to inspect, and if gone allow the diff to shift up and down with accell/decell.
I’d like to use a lifeline on searching that; I can’t find it.
 

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The car is in almost perfect condition.

Almost.

A vibration is plaguing the driving experience. Between 60 and 75mph the vibration is most pronounced, but it rears its ugly face at other speeds as well.

Sometimes the vibration seems to (briefly) go away entirely, while other times it's really bad.

When acceleration hard above 70mph it likes to rear its head, but also when coasting or maintaining speed. It's not dependent on engine speed.

I feel it on the throttle pedal and see it on the passenger headrest.

I don't feel the vibration in the steering wheel at all.

The back tires are new contis, the front tires are older somethings.

I've had 3 balances done, and had a wheel "straightened". I've also done an alignment. I've also replaced the rear flex disk. The disease persists.




WHY IS MY CAR VIBRATING?!?!?!!??!!!
My money is on front tires.


I would start with replacing the front tires. See my post here.
I changed out the center support bearing with no improvement on vibration or a slight whining noise.

I was told that the center support bearing rarely fails as the driveshaft itself runs almost perfectly straight between the trans and diff. I know that I changed out a perfectly good bearing as mine was free as could be.

It's the little things that plague these cars that takes away from the outstanding driving experience. I was driving today and couldn't get over how nice my car is running and driving. 15 years old and still a joy to be in!

Good Luck,

Bob
 

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Discussion Starter #14
OMG I FOUND THE SOLUTION AND BEST OF ALL IT COSTS NOTHING AND TAKES ABOUT 1 HOUR!

Turns out my front wheel bearings needed adjusting.
It takes about an hour to do, requires no special tools, and is a relatively simple job.

Here is an excellent instructional video:

Completely relieved the vibration at 70mph, the car is almost silky smooth.
 

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Given all the threads on vibration problems that had no resolution, I'll nominate post 14 for the Encyclopedia!
 

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Discussion Starter #16
Given all the threads on vibration problems that had no resolution, I'll nominate post 14 for the Encyclopedia!
Let me get through some testing first.
I just took it up to 70 mph again, and the satanic vibration returned. I'm going to double check the bearing tension tomorrow and report back. There may well be hope.
 

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Before adding to The Encyclopedia, would like to get a report after some mileage on the fix. So please follow up on this.
 

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I would get a dial indicator. I have been doing wheel bearings for a long time and was very surprised on how little .01-.02 MM deflection is. I used to do hand tight and back off a 10th or 12 turn. A 12th turn on my car with all new bearings was .07 MM.
That being said.. I did lunch a spindle and bearing set before I got the DI for more than that reason alone.
 
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