W124 Vibration at 80 MPH

[colingibb]

Hi,
My '92 300E rides smoothly up to just under 80 MPH. Once the car hits 80-85 which is the speed I usually cruise at, it shakes quite badly but will disappear over 85. The tires are Falkens which I have found to be excellent up to now and have about 6000 miles on them. The steering alignment was done about 1000 miles before the tires were replaced. I checked the front tires today and notice wear on the inner edge of both tires. Can anyone tell me what is causing this? Do I have to get the alignment done again? Thanks.
Colin Gibb.

[t walgamuth]

i would say an alignment is in order.

tom w

[neanderthal]

check your air pressures first and formost.
then get your tires BALANCED and rotated. see if the shimmy/ vibration changes from steering wheel to seat or vice versa.


failing that you have bigger problems. steering shock, trans mount, suspension bushings etc. all play a part.

[autozen]

You probably have two problems. Alignment won't cause the shaking you describe. I would rebalance the tires. As to the tire wear, it sounds like you have a towed out condition. I would check with other people around town to see who does the best alignment work. Check with the repair facilities for their advice. All alignment personnel are not the same. Also it is rare, but a steering shock can cause that shake.

[Bigpete123]

Hmm. You may have a mechanical problem, but I would also recommend slowing down!! The US doesn't have the autobahns as far as I know!!

[softconsult]

How many miles on this car? Could be ball joints, tie rods, differential mounts, etc etc etc.

I would find a shop with a Hunter Road Force balancer. In my experience this is the best balance around. Google on Hunter Balancers and go to their website. They have a shop locator module. This machine will give you a printout for each wheel. It will also pick up any out of round condition on a wheel.

I would use the dealer for alignment. Your's is obviously screwed up.

As to the counseling about not going 80, my comment is that around Atlanta you had better be going 80 in the 70 zones or you will be run over.

My '92 Sportline with 230K is vibration free to all the way to 100. I generally cruise at 10 over the limit.

Steve

[csnow]

Just because they aligned it does not mean that there were not worn components.

Check the idler arm bushings. I had very similar symptoms when mine were worn.

Check the suspension balljoints for play, but you must unload them to detect.
Support control arm with jackstand, then check for play.

[samiam4]

I'd spend a little more time trying to find the problem instead of throwing parts at it!

Sounds like paying an experienced mb mechanic an hour to inspect the car head to toe on a lift might be a cheap way to find the problem. Assuming you really want to do the repairs yourself.

I'd make sure all the front end parts are in good condition.

The toe out condition you described indicates the shop did not use the spreaderbar when aligning the car. It is to create road forces which spread the front tires outward at highway speed-then you set the toe.

Has this car always vibrated this way? Is this post tires? post struts??

M

[autozen]

Colin,
Since you are bent on pulling the driveline anyway, do yourself a favor and rotate the u joint while the front section of shaft is removed. There should be no catches in it except maybe at the centered position. If you feel any sort of catch anywhere off center. the driveline needs to be rebuilt. MB went to staked in joints like everone else. You'll have to send it to a rebuilder. Don't even try to do it yourself. The service I use is excellent and fairly priced. They include boxing and shipping in their price.
Power Train Ind. (800) 798-4585

I still think you might have a wheel balance problem or possibly an expanding belt on one of the tires. Swap front to back. I can't diagnose much closer considering the car I'm trying to diagnose is 3000 miles away.

[greasybenz]

It defenetly has something to do with the tires. When i changed the wheels on my SD to the 8 spoke 16in. wheels off a 93 s-class immedietly i had vibration at 50+mph. And i went to get new goodyear tires and get the car aligned it fixed the problem.

[colingibb]

I'm taking some vacation time next week, see if I can get to the bottom of this.
Keep you posted. Thanks again for the great advice everybody.
Later y'all,
Colin.

Originally Posted by greasybenz

It defenetly has something to do with the tires. When i changed the wheels on my SD to the 8 spoke 16in. wheels off a 93 s-class immedietly i had vibration at 50+mph. And i went to get new goodyear tires and get the car aligned it fixed the problem.

I'm glad that you have yours fixed, but just because that was the problem with yours does not mean that he has the same problem.

That said, much more often than not, tires/wheels are the source of vibration.

Have a great day,

[Ralph69220d]

I agree with the wheel & tire generally being the cause of vibration. One of the problems is that you can balance a square tire.

[autozen]

Larry,
Never thought of that. Thanks for the tip. I just bought an ultra sonic cleaner. I'm experimenting with gas injectors and fuel dist heads. I'll keep you posted. I'm having good results with the injectors.