Mercedes vibration nightmare again

[M104]

Well, this was the reason why i sold and replaced my previous car after replacing everything for almost no improvement and pulling my hair for over a year. And here i am dealing with this over again on my W210. I don't know, maybe the previous car created a trauma...

The symptom is a mild diffuse vibration and harshness that starts around 90 up to around 120 kmh usually (around 60 mph). I can't say i have a bad vibration or shake in the steering wheel, maybe very slight at times. It is intermittent and sometimes disappears for a few seconds, can't say if it's related to the asphalt or something else. I don't feel like it's worse under load. Wheels are torqued correctly to 110 nm and playing with inflation pressure has no influence on the vibration.

Tires: Yokohama BlueEarth 215/55R16, 7000 km.
Rims: Stock, look bad and corroded but don't appear to be bent visually.
Flex discs: No cracks at all, probably original to the car, original MB parts.
Carrier and driveshaft bearing: Can't say because of the heatshields but no symptoms of it being bad (heavy knocking under accel at low speeds/take off and vibration worse as speed goes up).
Motor mounts: Look perfect, original MB part.
Trans mount: New, original MB.
Rotors: New, no vibration when braking.
Front suspension: Everything tight except for a very slight play in a tie rod or steering ball joint. New sway bar bushings and links.

Dealing with vibration is the most frustating issue i can think of with a car, drives me absolutely mad! Any help appreciated.

 

[Danno]

How many Kms on the car?
Any out of spec play in suspension component is concerning.
Have you tried swapping front wheels to rear and rear to front?

 

[M104]

146 500 km on the odo right now. Yes i have done that and i think it behaves just the same.

 

[TCL]

Check the hood adjustment rubbers that you can screw in and out, If it has them and try taking any play out of the hood.
A friend had a 72 Cadillac Eldorado. That hood was about seven feet long and weighed about 200 pounds. He did everything
to the car for a vibration issue at 55 mph. New Michelins, rims, all front end bushings, shocks, motor mounts, both halfshafts and bearings. Same vibration at 55 mph.
I happened to walk over to the car and leaned on the hood one day and it moved up and down a bit. I adjusted the rubber adjusters to take up the slack and he never drove it anymore that day. The next day he came over my house and said the vibration is gone. The hood was flopping around, but nothing you could see from the couch like front seat.

 

[M104]

This is the last thing i would think about! I'm going to get my wheels balanced again at another shop today and ask them to carefully look at the rims and tell me if anything is out of true.

 

[Bailes1992]

I've had tie rod play cause vibrations before now.

 

[KrisZ]

You need to get the suspension inspected or inspect it yourself, Vibration doesn’t have to be linked to wheels, but oftentimes is caused by bad suspension bushings or worn components.
Mercedes has quite sophisticated suspension, so there are a lot of potential failure points that can cause vibrations.

 

[M104]

I have a slight clunk somewhere in the steering when i wiggle a front wheel but nothing that could be seen, i already have the parts and could replace everything but i have a hard time believing that a vibration would be caused by something that's not rotating. In fact i had cars with completely shot front ends and very good tires and balance and there was no vibration at all at any speed.

 

[Marcozi]

Were the bearing hubs perfectly clean when the new rotors were mounted? What brand are the rotors?

 

[M104]

Yes, i made sure everything was as clean and rust free as possible.

Just got the car back after having another shop balance all wheels. If anything it may be slightly worse. Before it was not too bad between 120 and 140 kmh, i haven't driven the car enough but it seems bad all the way from 90 to 160 kmh!

Are Yokohama tires horrible? I've just realized that over the years, almost every car i've owned without vibration issues had Michelin and absolutely all my cars with vibrations issues had other brands.

 

[goblin]

Not horrible, but Michelin is hard to beat, any way you look at it.
Could the tires themselves be out of round ?

 

[M104]

Nothing visually out of round either.

 

[97prizm]

This is the last thing i would think about! I'm going to get my wheels balanced again at another shop today and ask them to carefully look at the rims and tell me if anything is out of true.

I'm dealing with a similar issue on my neon and it's driving me crazy. Some roads are better than others but I truly think it's the tires that I have.

 

[M104]

I feel your pain. What tires do you have?

People around me told me i'm too picky about my cars but there's hardly anything that ruins the pleasure of driving as bad as vibrations problems for me.

I drive complete POS cars quite often and most of them drive smoother than my MBs and i can't tolerate that at all.

 

[ripcord]

Well... If your Mercedes is causing you grief, there is that Porsche you've always wanted.

 

[meep]

The Yokohama tires I’ve owned have been some of the most precisely made tires I’ve known. There are always outliers but I don’t think that’s the issue here. Loose/worn rubber bits which allow play can be an issue. Those speeds make me think tire, suspension, or driveshaft. Driveshaft shake is 3x the rate as wheel shake. Wheel hop is probably a slower shake, and would indicate need for bushing work or new dampers. The problem is *resonance* more than simply what the root cause is. Just that right speed can get the whole system to “ring” like a tuning fork.

 

[JHZR2]

If it’s like prior Mercedes designs, there’s a u-joint in there. It’s not really to change angles, rather to just allow some adjustment as motor mounts sag or other such things. They do sometimes get stiff because of how they are used.

 

[M104]

I can't find anything wrong with my suspension, neither could the mechanics who have seen the car, there's no play anywhere... I am so frustrated that i really don't want to drive the car anymore if it's going to be like the last one.

On the W202 i had before i did: flex discs, carrier bushing and bearing (multiple times), engine and trans mount (also multiple times), shocks, drag link, various tires and balanced many times, playing around with tire pressure, replaced rotors. At some point it got somewhat driveable, that didn't last and i sold the lemon and bought this one.

 

[ammolab]

“Road force ballanced”? Not just done on a Road force machine like Discount Tire does, but actually done by procedure where they measure lateral and radial runout of the wheel and tire and then match high to low etc to reduce the actual road force.

This isn’t often done even by folks like DT that have the machine

 

[M104]

Yeah i always wanted to get my tires "road force balanced" but i have no words in french to explain it and ask who is able to do it, or even if that's a thing here.