You will also want a large set of channel lock pliers to loosen that big nut so you can shorten the drive shaft when prying it off the rear end.
I'd suggest a good look see with a trouble light, before you buy parts in case your flex disks look iffy(little cracks in the rubber around the bolt heads). If they look bad you would want to change them while you are 1/2 way there.

__________________
Thanx,
Alberta Luthier
1983 300CD ('Stinky')155k miles, 2.47 diff, EGR removed, AAZ injectors with 265 nozzles from Sean,and vogtland lowering springs.
1984 300SD ('Old Blue')150k Klicks from Japan originally, came with rear head rests, no sunroof and never had an EGR

I can't tell what kind of car you have, however, I had a 88 300E, W124 that did this. There is a bulletin on it. The drive shaft is actually out of balance. Likely someone replaced some parts and didn't reassemble it correctly.

__________________
Bill

Backyard Shadetree Mechanic, 30 years running.

1987 300TD
1988 300E (sold, sniff)
1999 S320
1981 Volkswagen Rabbit Truck (Diesel)
2001 Ford Expedition
1988 Suzuki Samurai
On my list to buy: R129, for me, and a R107 for my wife.

I have an 83 300D Turbo.

I was actually thinking the same thing today. Is it possible for a mechanic, or myself, to disassemble and rebalance? How does one gauge that and determine the correct balance? A machine?

Thanks

W123 DS will not come unbalanced.

__________________
http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

Remember to mark with paint all the parts in the driveline which might be able to be put back together in a place different from where they started out....

I have a vibration that starts about 22mph and last to about 30 mph.
Not in the wheels, but feels more like it's in the rear......kinda a seat of your pants vibration........same thing?

__________________
81 Mercedes 300SD 289k.......SOLD
82 Mercedes 300CD 252k......slow ride

82 mercedes 300 SD...mi Unknown
83 Mercedes 300D ????ksniff..gone too
84 Mercedes 300D 148k........SOLD
85 Mercedes 300TD 386k and holding some one elses project

Yes, my vibration happens at higher speeds, but its not just a steady vibration, it is rhythmic, meaning that is constant cycle of heavier vibration to softer vibration. sounds like someone is moaning louder and softer. I believe my issue is in fact in the centerline bearing. makes sense.

I have the same vibration. I replaced the center support and bearing. It did not fix the problem.

__________________
------------------------------------------------
1985 300D Turbo Diesel 268,000 miles
1998 F150 4x4
2004 Honda Van
1970 Olds 455

http://www.peachparts.com/shopforum/...ine=1198976376

What is your next step? Have you replaced anything else already?
Engine mounts? Tranny mounts? Flex Disks? Wheel Bearings?

These are all items I have in mind and some of these items look like they have already been replaced by a previous owner. I suppose it could be an axle or possibly even an unbalanced driveshaft. I have heard contradicting theories on the driveshaft. Some say it is impossible for it to become unbalanced....then why, I ask, is it so important to make sure it is put back on the same way it came off? Some say to mark the driveshaft so it is easier to put back together. This leads me to believe if someone else has removed the driveshaft and put it back on the wrong way, it could become unbalanced and therefore create a vibration. Question is, how does one tell if a driveshaft is unbalanced and how does one rebalance it?

TGblanken, I seem to have the same problem, but its only really bad with weight in the rear. I took a trip to Miami, and had 3 adults in the back. On the way back home (70-75 mph highway speeds), that same sound you described started (it is rhythmic, meaning that is constant cycle of heavier vibration to softer vibration. sounds like someone is moaning louder and softer.)

After reading through MANY different threads, do you think I should start off replacing the Center Support Bearing? I checked ********az and they have a really good price on it.

My car just hit 299k, and runs like a top, especially with just myself in the car. Should I order multiple parts and just start replacing one at a time? Could the axles with worn CV boots have anything to do with the problem? Thanks again!

__________________
1985 300SD - 167k miles
1992 F350 7.3 (Soon to be converted to 2 tank Veggy/WMO)

It is possible for the driveshaft to become unbalanced, if one of the weights comes off. The more likely candidate is that the u-joint has become notched. The notch in the joint is very hard to feel by hand. This will give you the feeling of an out of balance. The U is a pressed in piece and is not user serviced. A high quality driveshaft shop can balance a MB shaft, but these are few and far between. Pressing in a new piece will cause a nice shaft to be out of balance Better off buying a new (rebuilt) driveshaft. It comes with a carrier bearing, and is not terribly expensive.

The MB shaft of this era comes apart just in front of the carrier, at the nut mentioned in previous posts. This is a splined piece, that if put back together one spline off will cause a true unbalance. The shaft is balanced and weighted as a unit. If you are taking apart the shaft, take a piece of tape along the axis across the spline (across the nut) and then some spray paint on the tape in order to get a nice sharp line. It is imperative to replace at the exact spline.

__________________
Mercury is a boxer

1984 300d
1999 Prelude
Medici road bike
Klein touring bike
Klein mtn bike