Mercedes vibration nightmare again

Didn't certain W210's have a bad harmonic balancer?
You are right, I think it was an issue with the M112 V6, mine has the M104 straight 6. The issue is not rpm related, it's not the torque converter either.
have you checked the rear diff/final drive? check for enough lash especially
There's no abnormal play anywhere in that area, i think that the issue comes from the front of the car as it is not fast enough to be a driveshaft issue.

Just spent two hours taking a good look at everything and at least one tie rod got slightly worse, there's a bit of play in the front bushing of lower control arms as well, would that be enough to cause this issue? I have to replace them anyway.

The other thing that seemed weird to me is that i couldn't tighten the wheel bearing more, i tightened the nut as far as i could but the bearing was still a bit loose.
 
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You are right, I think it was an issue with the M112 V6, mine has the M104 straight 6. The issue is not rpm related, it's not the torque converter either.

There's no abnormal play anywhere in that area, i think that the issue comes from the front of the car as it is not fast enough to be a driveshaft issue.

Just spent two hours taking a good look at everything and at least one tie rod got slightly worse, there's a bit of play in the front bushing of lower control arms as well, would that be enough to cause this issue? I have to replace them anyway.

The other thing that seemed weird to me is that i couldn't tighten the wheel bearing more, i tightened the as far as i could but the bearing was still a bit loose.

front issues would definitely be felt in the steering wheel first. the driveshafts going to each wheel are turning at wheel speeds btw....
 
I definitely feel something in the steering wheel but i'd say it is diffuse and comes from the front of the car and not really a steering wheel shake such as a missing weight. I am not too concerned about the rear axle, the two driveshafts usually start to fail at mega miles on those cars, quite unusual.
 
I definitely feel something in the steering wheel but i'd say it is diffuse and comes from the front of the car and not really a steering wheel shake such as a missing weight. I am not too concerned about the rear axle, the two driveshafts usually start to fail at mega miles on those cars, quite unusual.

it was a constant issue on older diesel mercs, the rear differential.
 
Heard more about the differential itself failing, indeed. I remember a friend having differential issues on two or three of the early diesel W124s he had.
 
You are right, I think it was an issue with the M112 V6, mine has the M104 straight 6. The issue is not rpm related, it's not the torque converter either.

There's no abnormal play anywhere in that area, i think that the issue comes from the front of the car as it is not fast enough to be a driveshaft issue.

Just spent two hours taking a good look at everything and at least one tie rod got slightly worse, there's a bit of play in the front bushing of lower control arms as well, would that be enough to cause this issue? I have to replace them anyway.

The other thing that seemed weird to me is that i couldn't tighten the wheel bearing more, i tightened the as far as i could but the bearing was still a bit loose.
You have a issue with the wheel bearing, you do not tighten the bearing nut as far as you can there is the MB spec using a dial indicator to achieve 0.01-0.002 mm end play but you can backyard it and tighten it just snug and back it off slightly. If you are tightening it that much and it still has play suspect a bad bearing. Yes it can cause vibration as can a bad LCA bushing.
Make sure the back of the wheels where it mounts to the hub and hubs are clean and free of corrosion.
 
You have a issue with the wheel bearing, you do not tighten the bearing nut as far as you can there is the MB spec using a dial indicator to achieve 0.01-0.002 mm end play but you can backyard it and tighten it just snug and back it off slightly. If you are tightening it that much and it still has play suspect a bad bearing. Yes it can cause vibration as can a bad LCA bushing.
Make sure the back of the wheels where it mounts to the hub and hubs are clean and free of corrosion.
Thanks, i will replace both front wheel bearings. Even as tight as the nut is right now i don't even need a dial indicator to tell me that it is too loose! The grease was nice and green around the nut but brown and nasty inside the bearing itself.
Use your smartphone with an app to detect the vibration frequency. That will reduce you to specific components at that frequency (drive shaft, wheel) and go from there.
Do you an app to recommend? I'd like to try.


I'll replace tie rods and tie rod ends, LCA bushings and bearings since they are bad anyway and finger crossed the vibration will be solved but my hopes are low. What is strange is how well the car rides otherwise on roads that are not the best.
 
Thanks, i will replace both front wheel bearings. Even as tight as the nut is right now i don't even need a dial indicator to tell me that it is too loose! The grease was nice and green around the nut but brown and nasty inside the bearing itself.

Do you an app to recommend? I'd like to try.


I'll replace tie rods and tie rod ends, LCA bushings and bearings since they are bad anyway and finger crossed the vibration will be solved but my hopes are low. What is strange is how well the car rides otherwise on roads that are not the best.

Throwing parts at it doesn’t help. Something either has play or it doesn’t. Many things can be a contributor though.

I use an app called VibrationAnalysis

 
Thanks, i've just found another similar app and on my short drive the peak frequencies were in the 20hz ballpark at speed but it was a very short drive.
 
It's a wild guess but i wouldn't be surprised to learn that they can't even balance a set of tires.
 
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Drove the car today and i have more data:

- Peak frequencies were around 15 hz when the vibration is as its worst and would increase with speed.
- The steering starts shaking around 90 kmh, 90 to 100 kmh appears to be the worst, at higher speeds i could still feel it in the steering but not as bad.
- The shake/vibration seemed to stop or lessen when braking.

I had this exact issue with the first set of aftermarket 17 inch wheels and big tires that came with the car when i first got it, balancing did not fix it. Got a set of original MB wheels for my model with the new Yokohama tires, vibration went away, there was still a slight shimmy from 90 to 110 kmh but would be smooth most of the time at speeds above 120 kmh and i wasn't too bothered. Since balancing again, it seems to behave like the first set of wheels/tires again.
 
Forgot the keep you posted but it might help someone. Guess the cause? First shop did a poor job at balancing my wheels. Second shop did even worse which resulted in 20 grams of inbalance on one wheel, 10 grams on the other. Third shop, i had to stand next to the guy balancing my tires and had to insist to set the wheels to zero grams of inbalance after hearing him say that 10 grams is not much and is acceptable.

In the end is was all down to laziness. Now the car is smooth even at 200 km/h (on german roads).
 
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Forgot the keep you posted but it might help someone. Guess the cause? First shop did a poor job at balancing my wheels. Second shop did even worse which resulted in 20 grams of inbalance on one wheel, 10 grams on the other. Third shop, i had to stand next to the guy balancing my tires and had to insist to set the wheels to zero grams of inbalance after hearing him say that 10 grams is not much and is acceptable.

In the end is was all down to laziness. Now the car is smooth even at 200 km/h (on german roads).

Likely, they did not have their balancer bolted to the floor. This has caused me problems multiple times
 
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