Hi,

Ok...so had the car test drove by a mechanic...he noticed the vibrations and said u-joint, sounds about right to me, had a truck wiht a really bad on, and I can see the similarities. I mean, it is a subtle sort of vibration, BUT...what kinda job is it, DIY? Pricey?

Thanks,
-Kurt

80 240D...vroom vrooom

find a good mb mechanic. you have flex discs , no u joints.

vibrations from wheels /tires /rotors /drive shafts/cvs are tough to determine

clunks going from drive to reverse would indicate a bad carrier bearing or flex disc. ( and/or motor/engine mounts )

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g-wagen

There is one u-joint and two flex disc. I would suggest getting underneath the car and taking a real close look at the flex disc. How many miles are on the car?

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Jim

If the u=joint is bad, get a used driveshaft, it's cheaper. The u-joint can only be replaced by someone able to strake it in place AND able to balance of the shaft. Typical driveline place will look at it and go "huh? What's that?", and won't buy the necessary adapters ($1500 for the set) to get the shaft on the balancing machine.

Check both flex disks and centering sleeves and the center bearing and rubber mount before messing about with the u-joint -- there is very little flex in the driveline, so the u-joint would have to be VERY shot to make it vibrate.

If you can move the shaft more than just very slightly with a lot of force in the rubber bearing mount, you need a new mount. An eigth inch by pulling on the driveline is WAY too much!

Also, a dying rear axle half will cause the same vibration as a bad u-joint. The difference is that the u-joint will cause the floorpan to vibrate at the bearing mount (beside the front seat) -- if you put your hand on the driveline tunnel and can feel the vibration most strongly at the rear half of the front seat, its the bearing mount, flex disk/centering sleeve, or j-joint. If the vibration is more to the rear of the car, it's probably an axle half.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

I know we're splitting hairs, but it's not a u-joint.

Mercedes calls this a center support bearing. It's not a u-joint in the sense that we are familiar with in rear wheel drive American Cars.

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

The Haynes manual shows a U-Joint which any red blooded American would recognize.... it is on the front of the rear driveshaft... and is just behind the Driveshaft intermediate bearing... which is just like the center bearing on my old Chev truck...

Don't kid yourself... this forum is Totally about splitting hairs....

But it started with MB engineers being so hair splitting in their designing....

If you REALLY want to split a hair Kline (who manufactures BIG driveshafts for paper machines) calls them crossing bearings. Took me a little while to figure out what in the world they were talking about the first time I heard it called that.

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Jim

Are you guys suggesting that I have a receeding hair line? or was that hair Kline?

The hair on my head is permanent, especially right down the middle. I call it "core" hair...lol

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

Really? Uh oh.... I could definitely move the thick shaft!! (I noticed that it's thicker than a Jeep Cherokee's...)

Now I won't feel too bad about replacing the driveshaft mount, bearing, etc.

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2008 BMW 335i Coupe

Holson:

Unless there are also grinding noises, you probably only need the rubber mount, not the bearing.

If you take the driveshaft out PLEASE mark the relative position of the two halves. MB doesn't key they spline (Volvo does, very nice!), and if you are even one spline off, it can go out of balance. Use paint after you clean the driveshaft well, anything else will probably wipe off leaving you guessing!. You do have to take it apart to replace the bearing, but not the rubber.

Spin the bearing when you get the driveshaft out, it will be obvious if it is bad. If there are any cracks in the rubber of the flex disks, or the bolt sleeves are displaced (I don't know if you have the hollow ones or not), replace them, too. Note that the front one is directional, it's marked.

If you can move the driveshaft around on the centering sleeve after you unbolt it from the flex disk, replace those, too.

Won't hurt to take a peek at the tranny mount at the same time, either.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

In my first attempt at driveshaft overhaul, I found that it was difficult to get the new center bearing properly pressed into the new center bearing mount. (They come as separate pieces)

Trying to drive the bearing in with a hammer was futile. It just doesn't drive in like a grease seal might. It had a tendency to pop right back out. Next attempt was using a vice. That was better, but I had trouble pressing the bearing in straight.

So, the result was a bearing pressed in using a vice that was not perfectly straight. This resulted in driveshaft vibrations at just about all speeds except 65+.

I probably would have had better luck using 1/4" steel plate in the vice jaws to more evenly press the bearing in, but I didn't have the plate and was in too much of a hurry to get running again.

So, I'll be back to the driveshaft "drawing board" again soon. I hope to develop a DIY procedure for replacing the U-Joint, as mine is not smoothly operating. It has a wear "detent" in the center of one direction of movement.

I'm going to go ahead and invest in a shop press from Harbor Freight so I can do bearing and ball joints properly.

Ken300D

Ken:

If you do not have a shop immediately available able and willing to re-balance the entire driveshaft (please check FIRST, with driveshaft in hand!), you will be sorry. I am, since the 220D has had vibration problems since I replaced the U-joint (twice, had a shop do it the second time, but they couldn't balance it....).

A used driveshaft is cheaper and easier.

There is a shop in California that will do them for you (and include a greasable universal, too), but cost is about $650.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

ktang,

You still haven't told us your location and how many miles are on it...

Totally. Fun!

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Ed
1981 300CD (Benzina)
1968 250 S (Gina) 266,000 miles!
1983 Alfa Romeo GTV6 (Guido)
1976 Jaguar XJS-saved a V-12 from the chevy curse, what a great engine!
1988 Cadillac Eldorado (better car than you might think!)
1988 Yamaha Venture (better than a Wing!)
1977 Suzuki GS750B
1976 Yamaha XS 650 (sold)
1991 Suzuki GSX1100G (Shafty Gixser)
1981 Yamaha VX920RH (Euro "Virago")
Solex Moped
1975 Dodge P/U camper


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