vibration on accelleration

[bob66542]

i took my 64 out for a drive yesterday and pretty much all of a sudden it has developed a bad vibration that seems to be in the first three gears when accellerating.cant make it happen in 4th, even if i try to accellerate quickly. from driver seat, it felt like it was comming from the pass. side rear.i jacked the car up on jack stands,put in neutral and spin both wheels and cant feel any roughness,u joints feel ok, but i can move the driveshaft quite a bit in the rubber at the center bearing(1/32 to 1/16" ballpark)surely thats not normal? i searched "center bearing" but there wasnt much there.how tough is this to change and is the bearing seperate from the rubber, or has mine broken loose? any advice would be appreciated-bob

65 SL 230 4-sp. purchase 12-08-03

[Cees Klumper]

I would definitely check out the drive shaft connections, try searching on 'flex disk' as I have a hunch that this is your problem. Don't drive the car until this is resolved.

e.g. have a look here: http://index.php?topic=4251+DISK

Cees ("Case") Klumper in Amsterdam
'69 white 280 SL automatic

[bob66542]

thanks for the link, Cees- i'll check it out tomorrow.So it is normal to be able to move the driveshaft up and down at the center bearing?-bob

65 SL 230 4-sp. purchase 12-08-03

[bpossel]

You mentioned in your post that you can move the shaft in the center...  You really shouldnt be able to move this unless you are in the process of installing it.  It needs to be tight.

Make sure the 2 bolts that hold the center brace in place are tight.  Also make sure that the driveshaft itself is tight.  You will need a 46mm and 41mm wrench for this.

Good Luck!
Bob

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bpossel  (Memphis, TN.)
'71 280SL  /  '97 E320

[George Davis]

The center bearing is mounted in a rubber bushing inside the aluminum bearing carrier.  The rubber bushing is hollow and probably a little bit flexible, and it is probably possible to move the shaft a very small amount by pressing or pulling on it.  As BobP said, the aluminum carrier needs to be solidly mounted.  The rubber bushing and bearing are both replacable, but it's more of a job than you'd think.  The flex disk is the more likely cause of vibration.

George Davis
'69 280 SL Euro manual

[waltklatt]

Also make sure the output shaft is tight and no wobbles.
Maybe the engine and tranny mounts need to be looked at too.
Walter
1967 220SL-diesel

[bob66542]

Cees, you were right,the flex disc at the front of driveshaft is shot-strings hanging out all over. cant belive i missed seeing on first inspection.are there any tricks i need to know when changing? i'll search flex disc.-thanks all,-bob

65 SL 230 4-sp. purchase 12-08-03

[glennard]

Bob, Just had a similar problem on a '86 190E.  The nut holding the three fingered yoke on the back of the tranny came loose.  The yoke has a interior spline that goes on the tranny output shaft.  The yoke fits in a  oil seal in the tranny housing.  When the flex coupling goes, the vibration tends to loosen the 24mm nut and ruin the oil seal(190E).    Also, there are some guide lines ()  on the use of the six nuts and bolts in the flex coupling.  Drive shaft, flex coupling, etc. system is one of those 'out of sight, out of mind' problems.

[bob66542]

i notice that prices for the flex disc are all over the place- $46 at k&k mfg. $100 at adsit, $240 from m-b -any advice? i dont drive the car hard,and it gets less than 1000 mi per year -bob

65 SL 230 4-sp. purchase 12-08-03

[ja17]

Hello Bob,

The job is fairly straight forward. Getting the complete driveshaft kit will make sure you get all the correct hardware and new nylock (locking)nuts. Installation must be done correctly or the flex disc will not last and damage to the driveshaft, or transmission may result. There is a lot of discussion on this. So do some searching.

 In short, make sure you have all the correct parts. Some bolts are longer than others and the washers must be located in the correct locations. The flex disc itself is installed in one direction and indexed with a tab (see diagrams).


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Here is Bob Possel's photo of his correctly assembled flex disc. notice the locations of the flat washers changes on the long bolts and short bolts. The flat washers are always positioned next to the rubber flex disc.


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Joe Alexander
Blacklick, Ohio

[Benz Dr.]

Different prices are often the result of different OE suppliers. The ones I use and sell are made by Jurid and are OE. If you just buy the disc it's much less than the whole kit that comes with 6 screws, nuts washers and two rubber seals.
There are some cheaper pacific rim parts floating around - be aware that some of this stuff is real junk and may cost you more in the end.

Dan Caron's
 SL Barn
benzbarn@ebtech.net
 slbarn.mbz.org
  1 877 661 6061

[bob66542]

thanks for the advice, guys, and also the pic's. i'll order parts next week and proceed when they arrive. ive read the threads, read the manual and think ive got a pretty good handle on what has to be done-now i just have to do it!-bob

65 SL 230 4-sp. purchase 12-08-03