stevebez

OK so after my trip up north here recently I got on the gas on a freeway on ramp only to enter a 50mph speed limit zone.

The trip down the onramp was solid but as soon as I hit the 50mph zone it felt as though I had square wheels.... I pulled the parkbrake handle (dunno why) and it improved a bit but was still there. Then after maybe 15mins it was completely gone. The road surface did change but did not seem materially different.

Is this due to the air suspension getting itself into a harmonic oscilation with the road surface.. what else could it be?

Rest of the trip home it was fine.

Ive noticed a number of times vibration problems have been raised before and at 14k miles I cannot believe its down to ball joint wear and tear and also the fact that it comes and goes is wierd.

I was quite surprised this last time and hopefully it was the harmonics of the road and the speed... but one thing I really hate about this car is the airmatic... allot more trouble (and weight) than it is worth.

Could be ..?
engine mounts
gearbox mounts
diff carriage
any bushings
airmatic
Quaife
shocks

Anything stand out/missed?

cal1

I get a similar vibration when my SL is cold and it is more noticeable in cooler outside air temps. Once the car warms up, the vibration almost completely disappears. I think some of the issue is the super soft tire compound (T1Rs). Once they warm up and get round again things get better. I just had the car into the stealer to check this problem out. They said my motor mounts were flat. Not leaking just flat. I had them replaced, but it does not seem to have improved much.

stevebez

Thats just the thing... we get a vibration, we find a fault, fix it and its still there - really wierd.

I was wondering if the car needs strut braces to firm things up a bit.

LADY_AMG

Is the vibration in your steering wheel or your whole car? I've actually never experienced this, so I'm curious if it's the suspension or the brakes.

Hammer Down

Could be your tires being cold or it could be your tires slightly out of balance or underinflated causing an out of balance feeling. Start with having them rebalanced and air'd up to 34-36psi. For a little softer feel go with 34 or for a stiffer feel go with 36.

cal1

Good advice. It is hard to diagnose problems when there could be multiple issues contributing. In my case which could be a bit different than the OP, I was quite sure I had some bent rims thanks to living right here in pothole city. I know, most people can make that claim. Turns out three out of four wheels bent. Wheels straight, air'd up good and even an alignment. Still vibration. $1,000 lighter in the pocket book and new motor mounts (third set by the way) and still the vibration. I thought tranny mounts, but the stealer said they were good. The vibration goes away above about 1800 - 1900 revs.

stevebez

The vibration was over the whole car and not in the s/w ... whats wierd is it went away after a while.... felt like a oscilation that was being amplified by the chassis somehow ... mbe I should ride my car in C mode setting for a while to get more travel out of the shocks and see.

I also have a vibration under braking - but traced that down to front discs (I hope) which are going to be swapped out soon.

cal1

Just wondering if the vibration changes or varies with engine revs like mine does?

stevebez

OK so drove the car today and she was - well perfect.

I am pretty puzzled.

Anyhow drove today in C mode and maybe the shocks / airmatic needed to stretch their legs a bit ... I actually think C is better for traction anyway as the weight seems to plant deeper into the rear than in S/S2.

In corners C is pretty hopeless....

O well c'est la vie... happy for now I guess.

cal1

I'm at risk of taking a bashing but, In corners the E is pretty hopeless

I know I know, my SL isn't a lot better

stevebez

I've been in worse but driven many alot better too.

Car is just too heavy, understeer on turn in, oversteer on power out, not much good going for it there, but then again I bought the car for the motor... As long as it can go straight ... I'm happy!

cal1

Yep, that's were the beast really shows itself. That visceral punch in lower back from the torque monster becomes addicting.

Jakpro1

I still can't believe the mod list is all checked off! I remember when it was just a couple X's.

Can't wait to see the new list on the tt car when you buy one.

Never have seen better systematic modding.

Dingleberry

check the coupler in the middle of the driveshaft - a common problem for cold only vibration

stevebez

Hmm ... thanks - its kind of where it felt the vibration was coming from - ill check it out thanks!

stevebez

You're too kind ... yes the P-car ... hmm gives me an idea.

How is your beast running?

cal1

Thanks Dingleberry this could be my problem too and thanks to the OP for starting the thread that I have been piggybacking off of.

AUS-E55

I've got the same sort of Vibration, at 70 MPH i get a viration through the whole car, I guess it could be my tires but it doesnt feel like it, if i keep the car at the same speed same RPM's the vibration comes and goes, It feels to me like the Tailshaft is out of balance or the center tail mount is screwed, I let you all know what I found if anything.

IndiumGreyE63

wow...I'm at 20K miles and nothing but smooth-as-glass road manners at any speed. I do have Michelin Pilot Sport Plus A/S tires (living in the rainy Pacific Northwest).

And believe me, squeeks, rattles, odd vibrations drive me ape-sh&t...

Jakpro1

She's doing great! Gotta couple of last mods to try before calling it quits on er like you did. I have come to the reality FINALLY that she just may never be a 10 sec car like Bassn and a few others and that is okay. Took nearly 40K$ to figure it out...but I think I finally got it!!

OH and on the vibration, nothing here at any speed. Wonder what the heck is happening?

stevebez

Its really wierd as I said before she is now running smooth again when used in C mode last - have not gone into S/S2 since. There are just so many things it could be... but the coupler sounds like it fits best - why only when cold though?

I need to check the parking brake tension too mbe I am picking up some drag from when I repaced rear discs. I think its either the centre coupling, tyres, shocks - might even have been the road - it was being repaired but I did not notice any major surface changes ... then again the vibration did stop after about 10 mins when I had that patch of "WTF!?!" ... but as long as she is behaving now then I won't complain.

Might have been a bushing that got stuck / trapped... ugh ill do my head in thinking about it.

Sometimes the beast needs to be enjoyed and not tinkered with... thats kinda where I am at.... bit like sound systems...!

cal1

I emailed my SA the suggestion of possible coupler in the middle of the drive shaft. He said the coupler would make noise at all times not just when it is cold. He also said new motor mounts at $1,000 would solve my vibration problem which it did not. I'll cut him some slack though. These damn vibrations can be difficult to diagnose.

maximus16v

Sorry for the old tread bump but I'm having same vibration issue when cold. At first thought would be driveline related so coupler makes sense but then reading more on here thought could be tranny.

Did you ever get yours figured out? Was it the coupler?

cal1

turned out to be tranny mounts.

maximus16v

Awesome thanks!