Greetings,
It seems as though the u-j on my 76 300D is on its way out. There is vibration only at start from a stop for the first couple of miles an hour and then there is no other indication at any other speed thereafter of any problem. There is no noise either. The vibration seems to come from the center of the car in the general vicinity of the tunnel.
Car has 392,000 miles on it, as far as I know, the d-shaft has never been serviced. In the last two years, motor mounts, engine shocks and tranny mount have been replaced, sub mounts as well.
Car runs well in all respects, but I had the mechanic look at that driveshaft. From him comes the word on the frayed state of the U-joint.
He recommends removing the driveshaft and sending it out to a shop that rebuilds them with american style u-joints. I don't know how much that will cost yet.
I suppose at this mileage there is no doubt, but how can I check the uey at home? And what are my other options? I had browsed the archives and it seems the two options are either a rebuilt unit or the mod with the non MB U-joint.
I want to do the German thing and keep the car as original as possible.
Thanks for the advice.

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63 220S W111
76 300D W115
2013 VW JSW TDI M6

previously-
73 280 SEL 4.5
86 300E 5 speed
2010 VW Jetta TDI M6

joshol,

How about a used driveshaft from an auto parts recycler?



P E H

Okay PEH,
Guess I'll have to price the 3 options and go from there.
thanks for the suggestion

__________________
63 220S W111
76 300D W115
2013 VW JSW TDI M6

previously-
73 280 SEL 4.5
86 300E 5 speed
2010 VW Jetta TDI M6

After spending a lot of time and many phone calls, I can say that not many driveline shops can deal with a Benz driveshaft.

The flex disks are the big problem in chucking a shaft into the most machines and no shops here in Austin have invested in the necessary adapters to hold a Benz shaft. Evidently, most people simply replace bad shafts rather than rebuild them. That fact did not help me one bit because I was eventually going to need a custom length shaft and, it would need to be balanced too.

Cities with bigger industrial bases may have a shop capable of dealing with and fabricating specialized driveline components. I found one in San Antonio:

Thrash Drive Shaft Inc
4838 West Ave
San Antonio, TX 78213
Phone: (210) 342-6622

I was in the Alamo city recently and had the opportunity to go visit with Thrash's shop foreman, Billy about my manual transmission/driveshaft project and my desire to have a rebildable u-joint.

Basically, he says that there's no advantage to retrofitting the joint so that it's greaseable/rebuildable. They used to do that same thing to Benz shafts and discovered that about 50% of the conversions would eventually get enough play in the joint to cause unacceptable vibration in the car. In addition, the cost for the necessary machining was expensive in relationship to buying a rebuilt shaft. He thinks that, for my project, I'll be much better off getting a remanufactured (also unrebuildable) shaft from their supplier in California and then letting Thrash perform whatever modifications I need to get it to the right length.

The price for a reman shaft that fits my 300TD is $315 + core. Shipping to San Antonio is included.

I consider replacment to be the right solution as opposed to the machining work and expense required to install rebuildable joints in the existing MBZ shaft.

__________________
Never a dull moment at Berry Hill Farm.

R Leo,
Thanks for that reply. I read that post in a search, I hope you didn't retype that
So, if the prices are competetive, the rebuilt shaft is the better choice due to the 50% failure rate of the modified shafts. Unless of course of used one is available and in very good condition. If they can rebuild em, cant I just send them mine and have them rebuild that? Well, guess I'll look around in Hemmings/ online for reman shafts etc.
Does anyone know offhand a good source? If not, I should do my homework before asking.
Thank you all very much

__________________
63 220S W111
76 300D W115
2013 VW JSW TDI M6

previously-
73 280 SEL 4.5
86 300E 5 speed
2010 VW Jetta TDI M6

If I were you, I'd call Billy at Thrash and see if they can have their supplier drop-ship one to you.

I wouldn't mess with one out of the a boneyard car. Here's why:
1) A lot of these cars loose their wheels and wind up on the ground, sitting on debris that can potentially dent or bend the drive shaft.

2) There's no way to tell if a shaft is slightly bent or out of balance until you spend your money, get home and bolt it in.

3) Most cars in the junkyard are high mile, poorly miantained vehicles. I have three junkyard driveshafts in my garage right now. Between bad center supports and bad U-joints, not a one of them is any darned good.

I only have the extra shafts because I was under the impression that I could use them for my manual transmission project and get a shaft house to machine and install a rebuildable u-joint. T'ain't so. At least not around here.

__________________
Never a dull moment at Berry Hill Farm.

Forgive the stupidity of my question:
What is the proper way for me to determine the degree of decrepitude of my U-joint?
It doesn't seem to vibrate all that much, but then again I don't know what level of motion I should be feeling.
My mech told me not to drive out of town in it.

At any rate I found something at www.driveshafts.com
that looks nice. Their engineering philosiphy is nice, check it out.

$355 for rebuilt drive shaft with grease nipple and 5 year 50,000 mile warranty. Shipping is included
It's 355 after the 75$ core.

Thanks for the help.

__________________
63 220S W111
76 300D W115
2013 VW JSW TDI M6

previously-
73 280 SEL 4.5
86 300E 5 speed
2010 VW Jetta TDI M6

This surely is one of the weak design points of the older MB diesel drivelines. Fortunately it is not a total disaster as the driveshaft removal and replacement is not beyond a reasonably experienced shade-tree mechanic.

In my case, a low speed vibration/groan was caused by the center support bearing and not the U-Joint.

If you have a really loose/worn U-joint, then it will have enough slack that you can shake the driveshaft side to side and feel the U-joint slop. It would have to be really really bad for this to happen.

In order to really determine if there is a problem, I think you would need to take the driveshaft down from the car and evaluate it where you can manipulate the U-joint by hand and turn the center support bearing around. Likely you will find the center support bearing needs replacement.

If the U-joint is not loose, but the center bearing bad - try replacing just the bearing and put it back on the car.

The wear characteristics of the U-joint typically make it develop a "center-detent" wear point, because really the joint doesn't flex all that much. This wear point doesn't necessarily cause any vibration - so I would not advise expensive driveshaft work just to replace a U-joint that has this kind of minor wear.

You would be surprised at the number of MB diesels that end up living a short life due to a total loss crash. And it doesn't take all that much to total one either. I found a good replacement driveshaft a PG Auto in Maryland for around $100. It came from a low-mileage vehicle that had the trunk crumpled up. When the junk cars come into PG they remove the driveshafts and keep them out of the dirt - it was in good condition.

Hope this helps - try the center bearing first.

Ken300D

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1982 300D at 351K miles
1984 300SD at 217K miles
1987 300D at 370K miles

Good points and, good catch on finding that driveshaft shop in Portland. Austin is a black hole when it comes to machinery or any real-world fabrication capability. However, if you are here in town, and need a quartz focus ring for a 300mm wafer etcher, you can probably get fixed-up pretty quickly. Bah.

My experience is that the center support failure/wear manifests isself in one or both of two modes. 1) a hissing, bad bearing noise when the bearing fails and 2) a fairly dramatic vibration under low speed acceleration when the surrounding rubber support is failing. This particular vibration, I believe, is caused by the shaft actually orbiting at the center support rather than spinning.

Replacing Marlene's center support cured the low-speed vibration but did nothing for the harmonic buzzing in the 57-60 and 65-78mph ranges.

Since I know her u-joint has 'detent' wear, and I can also feel a miniscule amount of play at the center point, the orbiting was probably the final manifestation of a u-joint failure, brought on when the vibration of the driveshaft (because of the u-joints) eventually destroyed the rubber in the center support to the point that it's vibration isolation qualities are nil.

I'm convinced that my buzzing won't be fixed until I do something about that u-joint.

__________________
Never a dull moment at Berry Hill Farm.

Great thread....just yesterday my 240D has begun to have some vibration at slow speed during acceleration. I now know what to look for and check. I was thinking a CV joint or flex disk. I'll try to crawl under tomorrow and check things out. I hate the thought of having to change the center bearing, but the PO had already purchased one, and I have been hauling it around in the trunk for 9 years now. I figured I would eventually need it.

Thanks to all who contributed the great info.....hadn't noticed any previous threads describing these symptoms.

__________________
1976 240D
1987 560SL
2007 E320 Bluetec
1998 C280 (now son’s car)
1982 240D Manual - Sold

Center bearing replacement is not too hard on a W123 (and maybe others, I don't know) with the right tools. Fortunately they are common tools.

You need a fairly large puller to get the old bearing off, a press or vice to seat the new bearing in a new rubber center support mount, and a section of pipe in just the right diameter so that you can drive the new bearing on.

Your driveshaft may or may not have alignment marks - because the two sections are correctly balanced when assembled only in one particuar way. So if the marks are not present, make your own with touchup paint or something.

I have a loose driveshaft in the garage and I'll do my best to get a picture posted on this thread of the match marks. If you don't know exactly what to look for they are not necessarily obvious.

Ken300D

__________________
--------------------------
1982 300D at 351K miles
1984 300SD at 217K miles
1987 300D at 370K miles

Thanks a lot for the information. I believe that between my factory manual, and this forum, I could get my driveshaft off the car.

I guess it doesn't take a lot of play in the U-joint to cause vibration due to the high rpms. I'll crawl underneath tomorrow and report back.

__________________
63 220S W111
76 300D W115
2013 VW JSW TDI M6

previously-
73 280 SEL 4.5
86 300E 5 speed
2010 VW Jetta TDI M6

Recently replaced the center bearing on my 1978 280CE (w123)

Marked shaft and flex couplings with white paint...couldn't see original marks (flex couplings can be left connected to shaft unless you are replacing them.....marked couplings as I didn't plan replacing them or their centering sleeves)

Main probem for me was undoing the sleeve nut on the shaft...........has to be undone to compress shaft and release the centering sleeves for removal.........tight space and 46mm nut !!.........my large 15"shifter (as we call it in Oz) went to 45mm........a plumber's wrench did the job

6" puller needed to pull bearing off shaft

The rubber mounting had fractured leaving the bearing to 'orbit around'

My symptoms were a 'flapping noise' that ceased at ~20mph

Will try & attach a picture..........Disc is an old thrust bearing which happened to fit the outer shell for pressing in to the mounting........the pipe was used to press the bearing inner on to the shaft

Attached Thumbnails

 

Why in the world do they not make the U joint itself rebuildable like every other car I have ever worked on I can't belive it could cause a blance problem.

I once had a 68 Caddy that had a bad center U joint the Dealer told me that it could not be rebuilt, but a mechanic friend that worked at the local Olds dearlership said that was a bunch of crap and got me the parts saving me several hundred dollars.I got a sneaking idea that somehow that MB joint could be rebuilt by a DIY'er.........
William Rogers..........

Possibly you might just need a mount. This is the part in the upper left corner of the picture shown in a previous thread.

I was in TN and my driveshaft started ('74 240D) vibrating. I stopped at a friend's house and investigated the vibration. I found the rubber in the driveshaft mount had deteriorated. I took some wooden clothes pins halves and stuck them thru the rubber mount all the way around. This may sound like a Rube Goldberg fix but it eliminated the vibration on the 1000 mile trip home.

My friend, who is a Mechanical Engineer thought I was crazy. But it was a temporary solution to the problem. We use to call them field expedients in the Army.

After I got home, I replaced the driveshaft mount and had no further vibration in the driveshaft.

P E H