I was on the highway a few days ago giving it an Italian tuneup and did a few pedal to the metal at 60 mph going up a hill. On the last one (din't want to do more), I felt a vibration in the chassis which was alarming (never experienced it before). I backed off the throttle and the vibration went away. I was worrying it may be the flex disk and drove it easy and got it home with no problems. Got it on ramps to look and both flex disks looked ok, no cracks. However in the front u-joint and center bearing area there are some issues and I took some pics. The plastic shroud is torn which covers the spline. Shaking the drive shaft I can produce a slight clicking sound which sounds metal to metal. Can you tell from the pics what parts need replacing?




In this pic, does that look like it's out of place and is that a crack? I have to have a closer look.

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

The Sleeve issue may or may not be related.

And while I cannot tell from the pics what is wrong there has been at least one Member who had a loose Collar Nut and the on the female side of the Coupling were eaten up.

Or maybe the Collar Nut is simply loose.

Nice pics.

Maybe the U-joint needs to be beaten on as in the below thread.
Sticking U-joint causes Vibration that Rips up several Drive Shaft Supports turns out to be Rusty Needle Bearings
W123 Propeller shaft vibration tears up rubber mounts, replaced nearly everything

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84 300D, 82 Volvo 244Gl Diesel

I posted to the thread you linked to asking the OP for an update. No reply yet. How is your staked u joint job from 2011 holding up? I hope I do not have to replace mine and will try that trick in your linked thread.

The secret to nice pics with my phone (Samsung Galaxy note 2) is to use flash, auto focus, and zoom as needed (4x max on mine). I touch the camera icon, the LED flash comes on lighting up the dark scene and auto focuses for 1/3 of a sec before snapping the pic. In that 1/3 of a sec, I can see the object being captured and move the camera to frame exactly what I want in the shot. I can do this with one hand and take a bunch of shots and choose the best ones. These phones are amazing!

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

my driveline has started to vibrate some as well.

recently the flex boot tore and made a terrible noise as it flapped about.

new boot listed for $8.86 @ my local dealer, pn: 202-411-04-97

new unit is more plastic-y but should function the same

waiting for more agreeable weather to crawl under car to replace & investigate source of vibration as flex discs, bearing & center support are reasonably new & of good quality.

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1991 300D

Carrier bearing worn out?

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Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

Looks like the rubber support has a tear.

With the wheels off the ground, (and the vehicle safely supported and blocked) and the trans out of gear with parking break off.
Turn the DL and see if the U-joint has any movement. Could be a worn Joint.

Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

Thanks for the replies. I'll do the tests Charlie suggested then take out the front driveshaft and carrier bearing to inspect.

This is a good DIY with pics for a 240D 4 spd but mine is 85 which is different. How to replace the driveshaft support (carrier) bearing - A step by step guide

The FSM is not that helpful with lousy photos and have you removing the exhaust, transmission mount and jacking up the transmission to remove the front driveshaft. Is that really necessary? If anyone have a good DIY with pics for an 85 please post link.

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Are the areas with the red arrows rubber that has been separated?

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

You don't have to remove the exhaust, but you probably will have to remove the trans. support (by jacking the trans) to get at the front flex disc bolts. With the center support freed, the driveshaft comes out to the rear. Of course, you'll have to loosen the collar nut and collapse the shaft to free it from the rear flex disc. The support wants to hang up on the parking brake linkage, but you can finagle it out.

I would go ahead and replace the center bearing and bushing if it was me. One of those "while you're in there's" and it isn't very expensive. In my experience, the bushing fails at the fold in the rubber and yours looks OK.

There's a reason the vibration appeared, probably separate from the center support. Check the condition of the transmission mount, the tightness of the output flange, the hitch in the U-joint, whether any balancing weights have come off the shaft, and the condition of the centering bushings at either end.

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1981 300TD 310k miles
1970 280sel 172k miles
1966 230 Fintail 162k miles

"Where are we going? And why am I in this hand basket?"

Those dark lines pointed by red arrows are shadows, not cracks in the rubber and is a figment of the camera flash! The center bearing support rubber is fine.



It turns out the 46 mm nut was loose by about 1 turn. I don't know where or when I got this big and heavy 1-13/16 open end from but it's just a hair over 46 mm, with the adjustable wrench (about 18" long) on the smaller hex on the shaft, I was able to tighten it up.





The torn rubber sleeve has a p/n 0115 411 0697 on it, but searching turned out it's the entire driveshaft Kardanwelle MERCEDES-BENZ W123 - 01154110697


I am not going to take anything apart at this point but will grease up the splines and go for some test drives. If no more vibrations, I will make some sort of wrap around rubber sleeve to keep dirt out of the splines.

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Can anybody tell me the number of splines on the driveshaft? Is it a multiple of 3? If not, then there is only one way that the yoke holes can line up, and mine is correct. But if it is a multiple of three then I need to try one or two of the other positions.

Got spline count from junkyard car, it's 27. So there are 3 positions where the flex disc fingers can align. I saw a photo of some marks on the u-joint yoke, so I'll see if one of the three positions line up the yoke with a shaft mark I found.