Drive shaft vibration center carrier donut question

[AllenF]

Hi Folks,

My 66 230 developed an odd driveline vibration after sitting a few months this winter.   I had already done the flex disc, but I went in an replaced it again along with the center carrier bearing and donut.   The replacement donut was not symettrical like the one I removed.   I couldn't find any oreintation information.   Any suggestions?   It's in, and the vibration is pretty much gone, but I am not sure I have it perfectly aligned. ??

Thanks in advance for any tips.

[dirkbalter]

Allen,
I replaced the donut as well. My replacement had the cavity for the grease nipple (early 230) molded in. That made the mounting orientation self-explaining. 
The drive shafts are balanced and it is important that they are re-assembled in the same fashion. (Not rotated on the spline)

[WRe]

Hi,
afaik this rubber mounting (A1114130012; 12/11/5 cm) was the same for all our cars and even for other MB models (W108, 111, 114, ...).
See https://www.pelicanparts.com/More_Info/1114130012.htm?pn=111-413-00-12-M22.
I found another part no. A1114130329 which should replace the first one maybe for a mount without the cavity for the grease nipple which disappeared from the late 230SL.
...WRe

[AllenF]

I am  reasonably sure that my original was symettrical, but it's hard to tell...could have become misshapen after 50 years, but it does not have the grease nipple hole.   Anyway, still eager to hear opinions as to whether the larger bulged side goes up or down.

[Pawel66]

Of course we have information on orientation. May come from Haynes, may come from BBB. Attached. Belly down, no. 4 on the picture.

[AllenF]

Thank You!   

Pretty sure I have it upside down at this point, but the good news is that I think I can spin the donut in place! 

I have the mercedes manual but this image does not appear in it. 

[dirkbalter]

I have the same as Pawel in the Haynes manual. In my BBB for the earlier cars (230) you can not see a difference in thickness.

[WRe]

Hi,
here the picture from the late models (1968, W108-113) workshop manual. Same Pawel showed.
...WRe

[AllenF]

It's interesting that the new (or replacement) rubber changes the orientation and angle to the driveline.   Seems like there are other discussion threads on the topic of "critical alignment"...  perhaps I should check the shim washer below the tranny mount before I call it done. 

Thanks again!

Allen

[WRe]

Indeed! ...WRe

[AllenF]

Brilliant...

I have a two post lift, so I guess I need to get on a drive on lift of get the milk crates out!   

Allen

[TJMart]

It's interesting that the new (or replacement) rubber changes the orientation and angle to the driveline.   Seems like there are other discussion threads on the topic of "critical alignment"...  perhaps I should check the shim washer below the tranny mount before I call it done. 

Thanks again!

Allen

As a suggestion, you should also check/replace the transmission mount. It will also impact the angle of the driveshaft. Use an original Mercedes transmission mount. A mechanic replaced mine with an aftermarket and it was not the same height and prematurely collapsed. Caused a bunch of problems because the driveshaft was never the proper angle.

[x046866x]

I'm doing the same job and noticed that the donut I removed was asymmetrical, part#108 413 01 12, but the part I received to replace it was symmetrical, part#111 413 00 12.  I asked Mercedes Classic Center to triple check and they assured me that the 111 part, the symmetrical one, was correct for my car. 

To add to the confusion; my driveshaft does not have the grease fitting that that symmetrical donut allows for (the hole in the side of the donut).  I do see that the 280 manual definitely shows the asymmetrical donut, but can't find the image for the 230SL manual (thought I had it....still digging).

I see that there is some adjustment room where you can tighten the donut ring and I'm thinking that could compensate.  I'm also not opposed to buying the asymmetrical donut (I can still get one and we're not talking high-finance).  My concern is proper alignment of the drive shaft, both laterally and longitudinally, but I can't seem to find a decent process.  Anyone find one?

[Pawel66]

I think: different types of shafts, different donuts.

I do not recall any grease fitting in 280SL there. The only one I am aware of is the one in the flange next to flex disc...

[x046866x]

No doubt things changed during production and, after 57 years and 250,000 miles, during the life of the car.  This grease fitting must have been to grease the bearing, but the ring around the bearing does not have a provision for that.  Additionally the bearing is "sealed" so it couldn't be greased after installation anyway.  I would chalk this one up to a production change OR someone before me changed the bearing and realized they didn't need the zerk fitting so they swapped the collar out for one on a 280 (which would explain the asymmetrical donut, BTW).

I definitely have the "older" shaft as mine does not have that nut on the front shaft portion and the male spline is on the front shaft (the female portion bolts to the universal housing).  Mine also has the floating split-spline in the rear portion of the driveshaft.

So I'm sold on the symmetrical donut now.  Does anybody know a good alignment process?  We're not talking rocket science, but I hear some saying lowering the car and rolling it back and forth, which I could see might influence some of the geometry.  I just want to make sure I put it back together as properly as I can.

If only these puppies could talk.  This particular car has been in my family since 1972 and my father worked on it since it was NEW....but alas he is no longer with us. 

We are not owners of these cars....just caretakers.

[AllenF]

Hmmm....now I am concerned that the donut that I replaced will not allow me to align the shaft.  Haven't gotten the car back on the lift just yet as the weather here in NH is not quite ragtop ready.   

[Pawel66]

I think part of the story is here (go to German language - always start SLS with German, some of the descriptions are omitted in English): https://www.sls-hh-shop.de/main/de/mercedes-230-280sl-w113/40-raeder-und-kardanwelle

The note says: Cardan: In February 1964, the middle cardan bearing was changed to "maintenance-free": Parts 70-75 in the picture were simplified or omitted (lubrication nipples and separate bearing seals), the sealing cap bearing (85) was introduced instead. Wheels + attachment: Standard rims of the W113 have a 14" diameter, but the 13" variant made of e.g. 220Sb was initially mountable. 08.'64 Transition from 5.5" to 6" width. There is no ABE or approval for 15" accessory rims (item 740008 on click area rims), but these require individual testing and registration. When changing between steel and light alloy wheels, please check the wheel bolt length.

I see in the parts list that the change took place at chassis 001982.

But on the donut shape - I am confused. I bought my donut from Mercedes - asymmetrical. This is what I saw on all the drawings, it did not raise suspicions. I see, however, that in the parts list PN A 108 413 01 12 (asymmetrical) is not for W113. for W113 across the models it is PN  A111 413 00 12 (symmetrical), as Classic Center said. Here it takes real knowledge and experience to shed light on this... or maybe more search on the forum.

As for the alignment - discussed on the forum. The "Porsche" school with chalk and the "piece of string school". You would need to do some search.

[x046866x]

The change of the bearing to a maintenance-free supports one of my hunches.  It doesn't help with the donut shape though.  There is no doubt that the later 280SL's show an asymmetrical donut and the early 230SL diagrams show the symmetrical donut, but with the zerk fitting.  I'm not sure why the changing of the bearing to a "maintenance free" would trigger a change in donut geometry though.

Using the immortal words spoken by grandpa in the movie Moonstruck "I'm so confused".

I'm going to re-assemble everything but before I lock up the lower transmission mount and cover I want to see if things appear stressed in any manner and, of course, if the asymmetrical donut will help.  I would be pissed if I gotta (almost) completely disassemble the shaft to switch from one to the other.

Damn old cars anyhow!

[Pawel66]

As per the parts lists, the change to maintenance free did not trigger the donut geometry. Actually, as I wrote, as per the parts lists, donut stayed the same all the time.

I have no idea why some of the cars (including mine) had the asymmetrical donut and all the sketches show the asymmetrical one. Well, as for the sketches - they might have been made "one fits all models", which would explain it.

[AllenF]

Thanks for the guidance.   I will get her back on the lift and report back on the alignment.   Since the driveshaft position will change with loading, I presume the critical alignment must be between the center carrier and the transmission?   Or should I plan on putting a couple dead bodies in the trunk to simulate normal weighting...

Thanks for all the help so far.

Allen

[x046866x]

@Pawel66 it appears you have a 280SL and I think that was asymmetrical the whole time.  Perhaps the asymmetrical donut somehow compensated for the change in the driveshaft?  I know the 280SL, and assuming 250SL (and maybe later 230SL), all had the slightly different driveshaft and maybe the asymmetrical donut was to compensate in some manner.

@AllenF interestingly the geometry between the flex-disc and the bearing inside the donut will not change significantly under vehicle weight load.  The rear of the transmission to the donut mount is relatively static, other than changes due to flex in the motor/trans mounts under different drivetrain load conditions.  The driveshaft behind this bearing/donut will change under all types of load impact but this is why they have the universals at each end of the section of the shaft.

So the only thing we really know is that we don't know why the donut geometry changed or what impact that might have.  My 230SL, with older driveshaft, had the asymmetrical but apparently wasn't supposed to...and worked fine for years. 

Here's what I'm going to do:
1) Assemble the front portion of the driveshaft by properly attaching to the rear of the transmission on the flex-plate.
2) Completely re-attach the rear of the transmission.  This means the rear mount to trans, the underlying plate to chassis, then lower transmission and mount that to the plate.  This will button everything up at the end of the primary drivetrain and put the rear of the transmission where it belongs.
3) See if the center collar falls naturally to the mounting location in the center of the car.  I would account for any flex from the weight of the front shaft, but given the flex-disc will be brand new I expect that to be minor and easy to account for.
4a) If the seat of the collar is unnatural in any way and it would appear as though the asymmetrical donut would make it better, then I'll buy the other donut, rinse, repeat.
4b) If the seat of the collar is natural and unforced in any way and looks likes it belongs there, then button up the collar where it is.  It will be interesting to note if it is different that the previous location (not sure if will be as the rest of the geometry is unchanged....just interesting)
5) Attach the rest of the shaft (yes, it will be a bit of a pain inside the car...but I think I can do it safely and confidently)
6) Drive around hoping I do not feel any vibration.

Wish me luck!

[Pawel66]

To note: there were more changes to the drive shaft, not only this bearing. The front piece changed, the joints have changed too.

[AllenF]

It's very possible that this car had the driveshaft replaced with one from a different/ later vehicle.  The prior owner had made some interesting mods to the car, to include using a 250SE engine...but they didn't realize the motor mounts were different so they changed the contour of the hood to make it fit.   Crazy.  Thankfully I had a spare hood and I was able to reweld and reshape it to fit perfectly.   But, given that they went to that kind of extreme nonsense to get the engine to fit it's unlikely they did research to ensure they were using the correct drive shaft.   Check out the "before" photo of the car with the modified hood...

[x046866x]

UPDATE: I followed the process I outlined earlier, including loosening all motor mounts and raising the motor a little to align things as close to where I think they belong as I could, and found that with the symmetrical donut installed and collar mounted the shaft seemed to stress the flex joint just a little.  I understand it is supposed to flex, but I didn't expect it to be flexed when the drivetrain at rest.  I think it is to flex to allow motion of the transmission/engine under different load conditions, but not 100% of the time.

I then looked to see if the asymmetrical rubber looked any better.  With the rubber piece removed I placed the collar against the mounting point and the shaft, at rest, sat about where the asymmetrical boot would position it.

I've purchased the asymmetrical boot and am waiting for its arrival.  I will install the asymmetrical boot and perform the same evaluation.  I will choose whichever boot seems to fit best. 

Stay tuned to this channel for more.