So, I'm in the process of replacing both flex disks and the carrier bearing. When I removed the driveshaft and separated the halves I noticed that whoever did this last did not use the factory marks(two raised marks on U-Joint and one raised mark on front shaft) to align the two shafts(this is an 85 300SD). I would chalk this up to a mistake but I did not notice any vibration prior to this and I have driven this car about 8,000 miles. Also, there is a series of brushed paint stripes on the front shaft. Did it come from the factory this way or is this a signifier that at least the front shaft is not original? If it is not original, is it possible that the shaft was balanced with the marks not alligning?

The principal of Occum's razor would dictate that the last person who worked on the shaft didn't pay attention to the alignment and that somehow it didn't matter. But I REALLY don't want to have to do this twice. So my question is, should I use the factory marks or should I align it the way it came out? (I made a crude mark just-in-case but it's possible I could be a spline off)

The painted strips are factory. You have 2 options, put it back togehter like it is, or line up the marks and give it a shot. The only risk is that you may have to put it back like it is if you try lining up the marks, so be sure to mark the current orientation first.

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

Do the driveshafts on the 240's have similar balance marks stamped on them?

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1981 240D 143k 4 spd manual -SOLD

2004 VW Jetta TDI 5 speed 300k -still driven daily

Thanks for the responses. If the painted stripes are factory I'm going to go with the factory marks and cross my fingers. The Carrier Bearing looks relatively new (I'm replacing anyway since I already bought the parts) so I think the previous owner/mechanic replaced it and botched the shaft alignment. Interesting that I didn't notice any vibration.

If I can hijack my own thread:
The rubber on the centering sleeves is toast so it looks like I'm going to have to replace them, too ($63 each from dealer, OUCH).
This is where the FSM gets kind of screwy. There is a specified distance that the centering sleeve is supposed to stick out past the flange. My existing distances are approx. 25mm front and back. The table in the FSM says:

126.02: front=30 mm rear=24.9mm
126.03/04, 126.1: front=20.4, rear=23.9

I would just go with the 126.1 spec. but the FSM seems to say that only the 126.02 5-speed has a vibration dampener and my 300SD clearly has one. So I'm a little confused about which spec to use. It's only the front that would end up making more that a mm of difference. I guess I could always match existing.....

I just redid the driveshaft in my '82 MT 240D, due to a partly torn center support that caused a low-speed rumble just while taking off or just before getting completely stopped.
With the car on jackstands, it was easier for me to separate the two halves in-car and remove them individually, than to try and withdraw & reinstall the entire assembled shaft.
I found no factory alignment/balance marks so I marked both halves before separation.
There was no balance-related vibration before the repair and so far, none since.

Happy Motoring, Mark

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DrDKW

Not that I have seen.

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

All W123s - if not all MBZ cars - came from the factory with the paint markings. On the 280E, they are yellow & blue.

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Don't Chrome them; polish them

Just thought I would Update:

Job is finished and was kind of a bear. If anyone else has to replace the centering sleeves, I was able to pull them out by drilling a hole all the way through (2 sides) and sticking an large allen key through them. I used a crow bar with a flat end to pry the sleeves out by wedging between the allen key and the driveshaft flange. I used a block of wood and a mallet to drive the new ones in.

The FSM gives measurements for the amount the sleeves are supposed to stick out past the flange but I discovered they are meaningless (at least on my model) There is a lip about 3/4" inside the driveshaft and once you drive the sleeves in that far they can go no more. I ended up with about 26mm sticking past the flange.

The FSM also mentioned removing the driveshaft in sections, but if there is a way to do this I could not figure it out. I had to drop the whole shaft and then disassemble. I also had to drop the exhaust. This job would have been a lot easier with a helper, as trying to get the whole shaft mounted on the trans and diff. in one piece by yourself is difficult.

I ended up reverting to the factory alignment marks (see previous post) and I notice no difference at all from the previous configuration. I hope I never have to do this job again....

I didn't want to try and wrestle the whole shaft assembly out and back in past the exhaust and brake cables and certainly didn't want to drop the exhaust or disconnect those cables either. First I marked the two sections for reassembly and unbolted the flexjoints., Once I had the center support bolts and spline-nut loose, it was easy to pull the front section free, then out past the tranny. Then the rear section with it's center support went out past the rear-end.

Happy Motoring, Mark

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DrDKW

RTFM. I don't have it here at work, but the FSM specifically states that all W123s after Sept 82 ( I think that was the date) have the marks. That said, it is very hard to see them if you don't know what you are looking for. They are sort of cast into the shafts.

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80 300SD (129k mi) 82 240D stick (193k mi)77 240D auto - stick to be (153k mi) 85 380SL (145k mi) 89 BMW 535i 82 Diesel Rabbit Pickup (374k mi) 91 Jetta IDI Diesel (155k mi) 81 VW Rabbit Convertible Diesel 70 Triumph Spitfire Mk III (63kmi)66 Triumph TR4a IRS (90k mi)67 Ford F-100 (??)

Mark, I was hoping your experience would be what I encountered. I'm not sure what year or model you have but I suspect it's different from mine and that you don't have a vibration dampener on the trans. side. Without the vibration dampener I think I could have done as you said. I also couldn't get enough leverage on the sleeve nut with exhaust in the way but I don't doubt it could be done.

Sorry to Monday Morning Quarterback, but dropping the exhaust and e-brake cable was painfully easy on my 300D. Took 10 minutes to drop them and 10 to reinstall when my work was done. It was then very easy to get the prop shaft installed single-handedly.

Granted I do have a southern car with no rust - if the exhaust bolts were rusty it would be more of a challenge. However, it's still only 2 bolts.

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1984 300D 193.5k miles
ASTM-certified B100 bio when able

The car is a stick '82 240D, with no vibration damper and enough room the get the big nut loose with a Channellock pliers. Plus I disconnected some of the shift linkage rods so I could lock the tranny in or out of gear as needed to position & hold the driveshaft at the best angle to access the big nut and flexjoint bolts. I also didn't need to do anything with the centering sleeves.
None of my diesels are turbocharged (One is an '84 NA Euro 300TD) so I have no idea if the exhaust is easier to drop on a turbo model, but my experience is that, after 27 years, exhaust nuts & bolts rarely come off easily, especially in parts of the world, including here, that often get well salted in winter.

Happy Motoring, Mark

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DrDKW

That's about the only thing that may be easier on the turbos- there is a joint near the front hanger that doesn't rust out that makes removing the back 2/3rds of the exhaust simple.

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80 300SD (129k mi) 82 240D stick (193k mi)77 240D auto - stick to be (153k mi) 85 380SL (145k mi) 89 BMW 535i 82 Diesel Rabbit Pickup (374k mi) 91 Jetta IDI Diesel (155k mi) 81 VW Rabbit Convertible Diesel 70 Triumph Spitfire Mk III (63kmi)66 Triumph TR4a IRS (90k mi)67 Ford F-100 (??)

Agreed. Dropping the exhaust was the easiest part of the job. On the 85 300SD there is no need to remove the parking brake.