Vibration on freeway @ 70mph+ 260E
 

In my 87 260E. It progressively gets worse as speed increases over ~70mph. It is just a vibration only upon acceleration. I have new engine mounts, tranny mount and flex disk. Rear flex disk also looks fine.

Any other ideas what it could be?

Thanks

I would actually start with soomething simple like checking the balance of your tires.

Yes. Either wheel balance or slightly bent inner/outer wheel lip. If you can swap wheels front to rear to see if the vibration changes...

hummm,

In the steering wheel or seat do you feel the vibration?

My Guess: Needs front wheel brgs, an idler arm bushing and dampener. If it's in the seat- I'd say check the center brg/support for the driveshaft and all the rear suspension.


M

The rims were swapped out only a month ago with balanced and aligned wheels.
I cannot tell if it is from the wheels or driveshaft...

Not sure if only durin acceleration helps narrow it down.

if the front wheels lost a weight or are improperly balanced you will feel a shimmy shakin in your steering wheel as the speed increases,you will also feel it as you apply the breaks,this may throw you off thinking your rotors are heat warped,i doubt it,if the vibration is in the rear,you will feel it in the seam of your pants,have some one check/rebalance all 4 wheels,find someone who has a road force wheel balancer,it uses a metal roller then applied a forced load on the tire as it spins,this is the most accurate way to locate the exact location needind the weight,it will also tell you if the tire has a flat spot or a broken steel belt,this is just a few pointers,you may also notice the vibration reduces or greatens the slower or faster you go,most vibrations are from 65 mph-80 mph,good luck,but def get the tired road force tested.

I do not feel it in the steering wheel or while braking. It disappears at any speed when I let go of the gas pedal. I cannot tell if it is front of the car or propshaft...Definitely not the rear though. I feel it in my seat.
As I said, all 4 tires and rims are fine. The tires are close to brand new, balanced and the car aligned.

The vibration definitely increases as speed increases over 70Mph. Anything under 70, even while accelerating is not felt, but as soon as it hits 70, the vibrations start under load.

Wouldn't bad wheel bearings vibrate all the time, not just under load? Would the steering dampener really cause something like this?

If you dont feel it in the steering wheel and you feel it in the seat how is the carrier bearing? when you did flex disk did you replace it? If this is new I would look at the new flex disk or like everyone said the tires again. Most likely the rears, easiest way to lose a weight, or the rear wheel bearings to the rears got loose or are going bad. Alignment would cause the wheel to "wobble" in the front for lack of a technical term.

Just ran into the same problem on 2 -124's recently and a 126 about a year ago.All 3 cars had perfect flex disc and vibrations at high speed.Found loose or slightly loose bolts holding the disc on all three. So just cause they look good give them a try.They may feel good by hand but put a socket on them and give it a try.The 126 came back a month later with the bolts loose again.Guess that one needed all new lock nuts or both flex disc.

My 300CE is driving me crazy with a vibration that ,after doing every thing i can think of,vibrates at 70 and up.Not real bad but i like a Benz to drive like a Benz.I think on the coupe its the rain grooves cut into the freeways in South Cal...On smooth roads it really smooth but on grooved roads it starts to vibrate and some roads are much worse than others.I am fairly certain its the brand of tire as Michlens don't vibrate and i got cheap and bought el-chepo's
Good Luck
Rich

Also echo the post to check your driveshaft carrier and the U-joint bearings. Acceleration puts a torque load on the driveshaft, and if the bearings are worn it will spin off center, hence the vibration under load only. I had this happen on my old 300E, eventually got so bad it would rub on the crossmember under heavy acceleration.

Bumping thread now as it's next on my list. I have the center support bearing. Is it pressed or anything? Easy to replace?

I don't think this is tires or rims because they would wobble regardless of load/no load. It begins vibrating at 65mph....I can go 80mph, let off gas completely and it completely disappears. Cant be rims.

Is carrier bearing same as center support? Never done anything other than the flex disk down there before.

Thanks guys

I'm not sure how different the W123 center support bearing is. But it's probably very similar.

http://www.peachparts.com/Wikka/W123DriveShaftSupportBearing

Occured to me...
Try holding it in third and doing same speed... if its engine speed related, it will occur at same revs. If its in the drivetrain, the extra power/Tq will make it worse...

I just replaced my center support , with new bearing on my 94 e320 with, your exact symptoms, vibration at full throttle in 1st gear gear, and rise in vibration the faster i went, i had vibration felt in seat, although wife didnt
know anything was wrong , bearing is loosely pressed into driveshaft, i used a press to remove old bearing , was easy to do, i also had a whine that i thought was transmission , after replacemnt whine is gone, smooth as butter once again,my center support rubber was broken all the way around, and i have 191k miles

Its not engine speed related -- its just load related. I can have the car at 5000rpm on freeway, let off gas and it disappears. Its acceleration only.

I'll start with center support bearing as I already have it in my parts box.

Do I need the 41mm + 46mm wrenches the same as the W123?