Hey folks, I've got a problem with the driveshaft on my '79 300sd, 189K- one of the bolts that connects the end of the driveshaft to the flex disc/diff has so much play in it, it has made a groove in the flange (see photo).

Two questions: 1: Do I look for a new driveshaft (and where would I look), or is a fill-and-redrill option worth pursuing at a machine shop, and 2: what would cause this to happen in the first place, and is there something else I need to look for to prevent it from happening again?

I'm looking to keep costs down, since I bought the car for $260 due to the driveshaft issue, a bad water pump, and the fact that it looks as though bears have been living in it.

Hoping to wave at all you MB dieselers on the road in 2005, thanks in advance for any and all advice.

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Hmmmm, I would expect a replace it.............

if you take it off to a machine shop remember to paine a line or something so you can put it back together, otherwise you disturb the balance.....

what I would worry about a drill and fill would upset balance....LOL like it isn't now already. Wouldn't hurt to find out anyway.

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Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
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Section 609 MVAC Certified
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"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche

A replacement drive shaft from a salvage yard would be the preferred choice.

However, you can run that drive shaft for an additional period of time if you immediately get a washer under the head of that bolt. The bolt has worn a groove in the flange of the shaft and is compromising its integrity.

It appears that this was caused by the bolt(s) becoming loose at one point and the loose bolts have allowed the shaft to rotate back and forth under the head of the bolt, causing the wear. It is interesting that the wear appears to be only under the single bolt, however.

Install a washer, immediately, under the head of the bolt and be sure that all the bolts are fully tightened. Mark the flange with an indelible marker, outside the head of the bolts, and check it after a couple of weeks to ensure that no rotation has occurred.