W124 Vibration at 80 MPH
 

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. :confused:

well, yes
 

i would say an alignment is in order.

tom w

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.

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.

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!!

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

Thanks for all the advice,guys. I will try a diifferent alignment shop, I have always been a little suspect about the Sears I went to in Warner Robins. See if I can find a shop familiar with Mercedes. The car has 207,000 miles and the steering shock was replaced recently along with new Bilstein struts all round.
As for slowing down, you are right Steve. You better be keeping a good rate of knots up especially on I-75 or I-285 in Atlanta which is part of my daily commute to work or you will be driven off the road even in a Mercedes!
I'm sure it's necessary to crawl around Seattle with all the rain they have, but not here in sunny Georgia.
Anyway, I am afflicted with Lead Foot Disease which in my case is incurable!
Later y'all,
Colin :cool:

Usually all the vibration issues I hear of are solved by correcting something within the tires. I had a Lexus LS that I used to commute in, and it had wicked vibrations at 80+.

Then I read that discount tire has this machine that'll balance the rim and balance the tire independently, then mesh the two into a solution. Worked great - solved all my issues for $35.

Thanks POS, I'll try Discount Tire in Atlanta, see if that cures the problem.
Colin :cool:

Actually we do have Autobahns. German engineering has always been superior to everyone else. Eisenhaur was so impressed with the Autobahn during WWII that the whole Interstate highway system designed in the 50s is patterned after the Autobahn. Once again American engineers screwed up and made perfectly straight roads instead of including the sweeping turns of the Autobahn. It seemed more practical until people started getting bored and fell asleep and crashed.

If you have not replaced your motor mounts, I would suggest them replaced. I had similar issue on my 560SEL. I could not tell by visual on the condition of the motor mounts, but once removed, one was totally worn and separated, and the other was wornout as well....

I would look to
1-the balancing of the wheels
2-to the schok absorber on the steering if you car has one.
3-are the wheel nuts correctly tighten?
4-wheels bearings

My vibration at 65 was just solved by new flex disc and center carrier / bearing.

Rich Mayer
82 500 SL

I agree that the tire wear may only be part of the vibration problem. I suspect the motor mounts,flex disc etc. are contributing to the problem too. I will check these components. Thanks everyone, I'll post again once I've figured it all out.
Colin

As I said, the tire wear indicates an alignment problem which WILL NOT cause the vibration you are experiencing. Also you can check your engine mounts by measuring the distance of the metal part from the frame. If it less than 12mm, you have lost some of the ethylene glycol that fills the mount, and the mount should be replaced. With a failed mount you should have a vibration at idle in gear. If your flex disc is separating, you should feel a vibration at almost any road speed under load.

I've visually checked the motor mounts and they appear to be in excellent shape, easily over the 12mm gap you suggested. The only indications of driveshaft problems are the vibration around 80mph and the gearshift from 1st to 2nd is a little jerky. Most other conditions the car is very smooth. I am going to replace the flex disks and center bearing to see if that cures the problem. It looks a fairly straightforward job to do myself. I'm now pretty sure this is the cause of my problem, I'll let you know what happens. Again many thanks for all your help.
Colin

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.

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

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.

Seems to me that some logic needs to be applied here. Before throwing parts at the problem.

1) Did the car display this vibration between 80 and 85 before the alignment and on the old tires? Yes or No.

2) Did the vibration occur after the alignment and before the new tires? Yes or No?

3) Did the vibration occur immediately after installing the new tires?

4) Did the vibration start to occur as the new tires gathered miles and
began to wear on the inside due to incorrect alignment?

5) The suggestion to move the rears to the front is a good way to diagnose the effect of wear. The rears shouldn't have worn on the inside. This would also eliminate the possibility that you have one bad tire in the front.

I have checked the front suspension and cannot find any signs of real wear. Everything seems to be in good shape. The car ran very smoothly for about 5000 miles before the vibration came back and I first noticed the wear on the inside of the tires. I will be getting the tires rotated and balanced this week at Sears (it's free with new tire purchase) and ask them to check the alignment again. I've had all my other cars aligned there before with no problems. Are Mercedes particularly sensitive regarding wheel alignment?
Also, after all your great advice, I agree the main problem is vibration from the driveshaft, so I will replace the bearing and flex disks, the front one looks like it's worn out and I like to replace parts like this as a matter of course.
I agree it may be best to take my car to a professional mechanic for at least troubleshooting the problem, but I have always worked on my own cars and see no need to pay someone when I can do the work myself, even a Mercedes, which for the most part has been a real pleasure to wrench on.
Thanks again everybody for your help. I'll keep you posted on developments. Stay tuned!
Colin

Is thre any damper on your steering?

Yes, I recently replaced the steering damper.
Colin

You could have had a professional diagnose the problem in about an hour. You've spent way more than you need to on parts, but hey if you're having fun. You are definitely different than most of the DIYs on this forum. Most don't want to spend the money on a single part until they are absolutely positively sure it will cure the problem.:)

I haven't bought any new parts yet. I've only replaced parts recently that were obviously worn out like the tires,struts and steering damper. I drive about 1000 miles a week and I need to keep the Merc reliable especially now it has over 207,000 miles on it.
I will definitely replace the flex disks etc. as the front one looks worn out.
For all the parts cost I think it is good preventative maintenance.
I will let you all know if that cures the problem. If not I promise I will take it to the dealer in Macon to let them check the car and at least do the wheel alignment again if thy deem that necessary.
Watch this space!
Colin :cool:

Find a tech who is accustomed to driving a car to check for vibrations. A tech will immediately be able to tell you whether the vibration is at wheel speed or driveshaft speed.

If it is at driveshaft speed, check the flex disks. If they are okay, put a washer between the carrier bearing mount and the body and retighten. Then see if the vibration is still there.

Good luck,

Is this a trick to put the needle bearings in the u joint at a different angle?

Absolutely sure the alignment is not correct from Sears.

Like I said- he may have the same hunter machine, but he won't own the spreader bar. The mercedes front suspension has rubber bushings.
If the guy has done a bunch of benz's correctly, he could get probably get it close without a spreader bar.

Agree with Larrybible. Take it to a mb tech and get them to drive the car and pay them to put it on a lift. They can pull and prod inspecting all the common things in about 15 minutes.


Michael

Yes, the washer will often get the u-joint away from the "notch" that is worn into it. I have seen this work more than once.

Have a great day,

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 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.:cool:

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,

wheel tire balance
 

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

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.