chikoo

I purchased my 2010 ML350 in January 2013.

Over time I have started to observe a weird behavior when going over uneven roads, esp when traveling alone. When the passenger side front wheel goes through a road dip, it follows the dip, causing the vehicle to dip to the right and then it bounces back to the left and then back to the right as it settles back.
For a comparison, going over the same roads in my Lexus sedan, I do not even feel the dip in the road.
I would have expected a large SUV to soak up road irregularities better than a sedan.
Is this how the ML350 behaves or is something wrong with mine?

chikoo

I should add that the suspension looks flawless visually. There are no leaks and height is still UP there. When loaded, the dips are felt much less. But that is 10% of the time. Rest of the time, I am alone in the vehicle and it is annoying as hell to bounce/jostle around in the seat over every bump and dip in the countryside roads that I drive on.

chikoo

update: I lowered my seat all the way down and drove over the same road. The jostling around is now down by 60%. wow. didn't realize the magnification of the bumps that occur simply due to sitting higher.

Kiwi Ed

This seems typical of the W164 ML and is what pisses us off most about our ML320 CDI, it also has airmatic, other wise its not too bad.

docvb

have a suspension shop check for a loose tierod or other part. Something's loose up there. Had the same problem with darting after bumps or road joints.

chikoo

I played around with the seat settings and found a comfortable position where the jostling is just about like a Lexus RX-350 F-sport. Who would have thought the seat position would have such a drastic impact on how the ride feels!

N4HHE

I think the shocks are bad on my ML. Dealer says, "they are not leaking therefore there is nothing wrong." Must make time to talk to an independent mechanic who knows how the vehicle is supposed to ride. Tempted to just buy a set of Bilstein HD's and install myself but if it is to be done any time soon its best I have someone else do it.

Am afraid to put OE shocks back on it because I don't like the way they ride and don't like that I didn't like them at only 45k miles. But am also concerned that the HD tuned shocks will make it worse in the other direction.

docvb

the darting on bumps indicates a worn tie rod or bushing. get it fixed before it totally fails or something happens at high speeds. Been there, rolled it (non-MB).

chikoo

N4HHE, hows the tire wear look like? A good sign of bad shock is scalloping of the tires. I had the same sit with my Lexus and ended up changing shocks on my own. I learned later that i could have take an oil dropper and squirt oil own the shocks such it looks like it is leaking and it will be covered under wty.

Kiwi Ed

Nothing worn / loose only done 49k Kilometres (30k Miles), no change from new. Not talking about tramlining, bumpsteer darting from side to side etc.
As chikoo describes more rocking from side to side on rough roads 'suppose the roads are smoother in Germany where they set them up.

chikoo

Kiwi Ed, as an engineer I have analyzed this issue and figured out the real problem and solution.

The W164 seating allows one to seat very upright viz almost a horizontal seat bottom and a perpendicular seat back, and that too quite high. The problem is that this coincides with the rocking and pitching movement inherent in any soft suspension long travel suspension.

The solution is to set your seat position such that you are not seating in the planes where this movements are maximum. The ideal position would be where your seat bottom is inclined backwards (butt portion lower than thigh portion), and your vertical seat back is also at an inclination, proportionately.

Try that out and report back your results.

chikoo

Here is how it looks on my ML350 right now and before it.
Amazing application of theory.

chikoo

Finally found the answer to the weird ride feeling I described. It appears that the front sway bar bushings were worn, and jam stuck, not allowing the sway bar to swing. Because of this, the tires would fall in the dips, rather than allowing the suspension to extend into the dips, causing the bobble head effect. Once my front sway bar bushings were replaced, my ML drives like I expect a Luxury vehicle to drive on those rough roads. Smoothly.

Gridirongreat

Glad you found the answer. If mine begins doing this i'll be sure to remember your post. I would imagine the fix didnt break the bank either which is great. Did you have MB do the repair?

chikoo

I got it done under warranty. I will look up the invoice and see the cost breakup dealer charged MBUSA.
The part# used was this : 164-323-11-85 (rubber mounting)
Price : $20.25
http://www.pelicanparts.com/cgi-bin/...Bushing%2C%20#

chikoo

I did a bit more research and "Sway Bar Binding" is the issue I was facing.

example: http://www.benzworld.org/forums/w203...-bar-help.html

chikoo

My rear sway bar had some squeaks and rubber bushings looked OK. So I sprayed them with Liquid Wrench penetrating lubricating oil and no more squeaks.