140 Series vibration - maybe driveshaft?? - Page 2 - PeachParts Mercedes-Benz Forum

peter210 · #16 06-03-2003, 10:24 PM

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

JimF · #17 06-04-2003, 12:17 PM

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.

Folgado · #18 06-04-2003, 03:56 PM

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

peter210 · #19 06-04-2003, 04:04 PM

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.

oldsouth · #20 06-04-2003, 04:09 PM

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.

peter210 · #21 06-04-2003, 04:14 PM

I just can't wait for the results.

Folgado · #22 06-04-2003, 07:20 PM

"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.

JimF · #23 06-05-2003, 02:14 AM

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.

Folgado · #24 06-05-2003, 12:21 PM

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

JimF · #25 06-05-2003, 02:53 PM

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.

oldsouth · #26 06-05-2003, 05:24 PM

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.

JimF · #27 06-05-2003, 06:35 PM

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

peter210 · #28 06-05-2003, 06:48 PM

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

albert champion · #29 06-05-2003, 07:52 PM

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

oldsouth · #30 06-05-2003, 10:07 PM

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.