140 Series vibration - maybe driveshaft??
 

I installed new tires and went to the dealer to have them balanced and an alignment. I also had the engine mounts changed out. The tech called me and said that there was a vibration at around 60 mph. He said after balancing the tires he re-balanced them again to make sure it was not the tires. He said that the driveshaft, where it goes into the transmission was slightly worn and recomended replacing the transmission mount to bring the driveshaft back up a little. (The engine mounts raised the engine about 1-1.5" and changed the driveshaft angle). This healped a little but the vibration is still there. His next recomendation is to change out the driveshaft (very expensive). My question is -- would new flex disk help the situation any? Has anyone else had this problem? Sure feels like an out of balance tire to me.

vibration...for what its worth
 

a couple of suggestions that you may want to try before driveline work... if you still think it is tire related, try rotating the tire /wheel assemblies from front to back, and also make sure that the lug nuts are hand torqued to spec.(I've owned other vehicles where the torque value is critical to proper rotating balance) I'm not sure what balance machine your tech has, but other threads here indicate that there is a balancer out now that is extremely accurate, you may want to find where one is and give it a try. The dealership that i frequent has a machine that will apparently identify such things as a thrown interior belt. (maybe he is bs'ing me, not sure)
good luck, let us know how you make out.

The "other balancer" referred to by mithra is the Hunter GSP9700. To find a shop near you that has one, go to: www.gsp9700.com.

Before you resort to that though, make sure the tires are DYNAMICALLY balanced with weights inboard AND outboard. It is very common for shops not to use weights on the outer lip of alloy wheels because owners complain about scratching their wheels. These cars have nimble suspensions and wheels that are not dynamically balanced will vibrate, period.

Also, if the flex disk was bad enough to vibrate, you would be able to tell by a quick glance. It would be in pretty bad shape. If it looks good and wiggling it shows no slack, then it is not your problem.

Good luck,

thanks Larry
 

that is the balancer that the local dealership has; I couldn't remember the model, but I remembered that it had a load wheel and that it was a gsp. amazing device.

You may also see if the tech recalls how much weight was used to balance your new tires. If they needed upwards of 5 oz. per side (inner and outer), you could have him break down the tire on the rim, turn them 180 degrees, reseal and rebalance them. Big 16 inch tires are a lot harder to balance than 13 inch.

I had my driveshaft replaced on my 300E because it would make knocking noises under acceleration. I highly doubt that a driveshaft could cause such a vibration. I dont even want to think how much a driveshaft costs for a W140.

I have '98 S500 and I have been experiencing the same problem. For a very long time I didn't pay much attention to it, but recently it really started to P me off. My tires were balanced 100s of times with MB weights on Snap-on machine and nothing. Never mind mentioning suspension problems. I take care of this car better than myself and there is nothing to look for. Driveshaft? Possible but very unlikely. I had a problem with the driveshaft on my '97 E320 (crap) but only due to dummy mechanic who took it off split it w/o marking and then never put it back the right way. Back then I felt vibration at low speeds already, therefore I don't see any reason for untouched driveshaft to just "go bad" for no reason. They last forever. On the other hand I have the same car with the same problem. Interesting isn't it? I'm pondering... When my tires were balanced I've noticed that the outside of the tires where the thread is does not spin evenly but "jumps" up and down as the tires were not ideally round. Defective Michelins? What do we do guys?

if it is the driveshaft...
 

Check the driveshaft and make sure the balancing weights did not fall off. As tiny as they are I bet they do make a difference.

and if you do need to replace it, find a used one first at www.car-part.com great resource for used cheap parts, especially for parts that last forever.

xp

No sign of missing weights. I've checked. My car is more than pampered. Regarding your www.car-part.com it sure is a very good source for used parts but I'd never buy a driveshaft or similar parts in such case. In such case... I emphasize. How would you know if the one you get does not have missing weights? Betterr to have your balanced.

Driveshaft linerity is an issue with the 140 chassis. There are driveshaft alignment diagrams and measurements in the "Popular Mechanics" CD-R. The info is supplied by Alldata. I got mine at PEP BOYS for about $29.99. It is internet interactive. You have to be on line to access the information. You can also download the info at www.alldata.com. for the same price. I prefer the CD-R from the auto parts store. Don't replace your driveshaft.

I got a brand new differential for my 190 using car-part, it had 17000km on it cause the donor car got rear ended. Since I put that differential in, the car floats on the roads, it used to vibrate in all sorts of ways, no more. In worst case scenarion, I'd go look, you might get lucky and find a donor that was even more pampered then yours, a lot of people, including me love these cars so much they forget to eat and breathe :)

xp

I agree with you MR. Goodwrench or rather GM? No offence...
But we haven't yes determined the problem causing the vibration. There are cars that I know from CLS limousine co. (you must know them since you are from NY area) they are abused, driven hard and with high milage and do not have this problem. My next step is to replace Michelines for a brand new set under manufacturer's warranty and see what happens. I'll spend no money and wind up getting a set of new tires...

XP190, true but it is different when you have an evident problem like you had with your differential. It is noisy, it vibrates and all kinds of things it just needs to be replaced. The subject we are discussing here is not a matter of replacing a d/shaft but rather determining the problem first and then taking appropriate steps.

Well, yesterday I put the car on a lift and looked under it real close. I can grab the driveshaft with both hands and twist it back and forth and there is a little play but I think all of it is inside the transmission. I can push up and down and there is a very slight play felt but I think it would not cause any vibration but not sure. The flex disk look and feel tight. There is a long aluminum pan between the exhaust pipe and the driveshaft and I did not remove it to look above, but everything feels tight. The size of the shaft looks to be bigger in the back than in the front so there is some kind of transition or coupling above the pan somewhere.

I stated that the dealer replaced the engine mounts and the transmission mount. I looked at the transmission mount and it looks like there is slack between the rubber part in the middle and the rubber that surrounds it. Is this normal or should the rear transmission mount be tight between the two rubber pieces?

I still think it is a tire problem. If a tire is out of round or bad, would it show up on a balancing machine?

Guys, I can't offer any advice, but I sure hope someone figures it out. I have a 93 140 with the same problem. Mine is most evident at freeway speeds.

Guess what! I just spoke to my friend who is a mechanic at MB dealership, and before I even finished explaining the problem he said "replace lower ctrl arm bushings" My 140 had them replaced less than 15K miles ago and he still insisted on having them replaced again. It's hard to believe and I'm now debating if I should have it done... Money no object but my time for sure is...
I never trust anyone.... he he :p

Had the same problem . . .
 

and the 'fix' was new tires (3 of the 4) and a careful dynamic balance on the Hunter DSP9700.

The Hunter can also diagnose out-of-round [oor] wheels as well as tires. My wheels were ok but the tires were oor. Replaced them (actually replaced all four) and the vibration stopped.

The vibration could be felt in the steering wheel, so it's ususally the front tires: if in the seat, it's the rear ones.

Hello Oldsouth,

I own a 93 S500, and I had that problem also.
If that is like you describe, believe me that you have a damaged transmission shaft. If you fell the vibration on the steering wheels it is probably from the lower arm bushings, but if the vibration is felled all over the car the problem is definitely the trans. shaft.
The reason is that the “cardan” in the middle of the shaft becomes damaged with miles.
In my case I had to replace the complete trans. shaft US$ 1000 without man work.
YES it solved the problem but the W140 will always have some vibration at low speeds, but of course nothing comparable to this.

I hope this may help you.

Folgado
S500

I'm sorry but I strongly disagree with you. In the first place I don't believe all internal guts in '93 and '98 tranny are identical. Secondly the vibration is stil there when the car is "rolling" with tranny in neutral... No way.. It can't be.... On the other hand similar problems would be posted long time ago. MB tranny go bad @ 20-40K? Sure it happens but not generally... They last forever.

I will let yall know tomorrow. I am set up to have the tires balanced on the Hunter 9700 tomorrow in a nearby city. Then I will know if the tires are out of round.

I just can't wait for the results.:)

"Secondly the vibration is still there when the car is "rolling" with tranny in neutral... "

The gearbox disconnects the engine from the shaft not the shaft from the back wheels!!

When you are rolling the transmission shaft is rolling as well.

YES the gearbox is different from a 93 to 95 S500, but the shafts are exactly identical.

The trans shaft only last in decent shape for 200.000 km, and if you run with the engine mounts dead it will go bad much sooner.

You can forget about the balance, with the W140 power steering any minor unbalance is felt in the steering wheel. That’s why they always have a slightly steering shimming.

Folgado, that's not necesssarily . . .
 

correct: I do agree that a 'bad' or incomplete balance will reflect in the steering 'wiggle' but that's because it's not done properly.

My S500 suffered from this problem but when the tires (Michelins) were changed to "in-spec" tires and properly balanced, there is absolutely no 'wiggle' in the car at any any speed.

It takes in-spec tires AND the man performing the balance. BOTH must be right but it's very achievable.

What you mean by "in-spec" tires Jim?

Sorry, that's a GSP9700 term. . .
 

that essentially means the machine can check that the tires out-of-roundness [oor] and weight balance testing.

3 of the 4 tires that were 'given' to me when I bought the car failed this test. Plus the balancing of these tires is almost impossible. So the car had great shimmy/wiggle in the steering wheel at 55 - 60 mph.

So the dealer (Discount Tires) gave me an adjustment for the new tires (very reasonable). Then when balanced on the Hunter, the car shows no 'shimmy' or steering wheel 'wiggle' at any speed.

You are correct that the 140 series is very 'sensitive' to any imbalance in the tires and/or wheels.

Well, it's the tires folks. They were simply out of balance. That is the first time the Mercedes dealer did not do a good job of balancing. I am impressed with the new Hunter machine. It checked the wheel AND tire for everything imaginable.
But, the guy at the tire shop said he had wheel weights for a Mercedes and come to find out, he didn't. He ended up using stick on weights on the inside of the wheel. He said he would order some proper weights and redo the job at no charge. I have heard that the stick on weights are not as good of a balance as weights on the inside and outside of the wheel (though it did do a theoritical dynamic balance with two sets of inside weights - one on the inside edge and the other as far out as possible). Anyway - now it is as smooth as silk.

Well, I'm glad that. . . .
 

you're glad! Makes a big difference in the car's handling.

So much from replacement of the tranny shaft... I had to stick it in.. Typical of me... Sorry :o

i enjoyed reading this discussion.

i am surprised your benz dealer performs balancing - generally they sub that out. and mark up the job considerably. when the service manager at intercontinental motors was a long time dealing with me, he would recommend that i just go directly to his sub for any tires or balancing.

and i have always found good balancing to be a toughie. my mechanic will not mount or unmount tires, he subs that out, but he always does the balancing. he has no confidence in most tire sales shops.

he also has an interesting rule in his shop, every time a car comes in, the wheels and tires are checked for balance before the car goes back out.

lastly, it has been my experience that new tires may need re-balancing within the first 500-1000 miles. and almost always after a panic stop[the tires rotate on the wheels].

balance. an important concept. in golf. in life. and in tires.

a votre sante

The dealer has always (up to now) done a good job of balancing. I am surprised though that they do not have the top of the line machine. Especially at the rates they charge. The 9700 will even give reading in metric units, easy with the Mercedes weights - no converting.
I like the Mercedes weights, no scratching the wheel.

I'm very glad you solve your problem.
I'm not sure if a machine like that is available in Portugal.
Regarding the transmission shaft I think that a 500 will damage it sooner because of the higher power and torque, in my case I had no chance unless replace it.
Well I think I already replace every thing in this car...
It should be an interesting point of discussion... W140 owners repair list..........

How can we test the trans shaft? I continue to feel vibration all over, even when I'm on the freeway and the car is in neutral.


[QUOTE]Originally posted by Folgado
[B]"Secondly the vibration is still there when the car is "rolling" with tranny in neutral... "

The gearbox disconnects the engine from the shaft not the shaft from the back wheels!!

When you are rolling the transmission shaft is rolling as well.

YES the gearbox is different from a 93 to 95 S500, but the shafts are exactly identical.

The trans shaft only last in decent shape for 200.000 km, and if you run with the engine mounts dead it will go bad much sooner.
QUOTE]

I Had Same Problem With A 600sel And 300 Sl Vibration At 55 To 60 Mph That Goes Away At Higher Speeds

Both Times It Was The Flex Disks Even Though They Looked Alright

It ended up being my motor mounts. Replaced them and everything is like new again.

If the vibration is during acceleration (load) and goes away when you let gas pedal then you can look at the driveline components, but if it is at certain speeds and especially if you feel the vibration in the steering wheel then look at the front wheels alignment and balance. Also for the back wheels check the balance of the drive axels, by suspending the car and running it at the speed where the vibration occurs, loose CV joints also can cause vibrations.
I hope this helps.