I am chasing a serious driveline whine/roar in a 300 SD (190K) I just bought. At highway speed it sounds like white noise AM radio static. Not much vibration felt, but what I do feel shouldn't be there. Diff oil is fresh. Halfshaft boots are cracking, but intact - I am planning to go ahead and replace the axles. Throwing the cheap parts at it first, I'm now changing my driveshaft center support bearing, and discovered a bad u-joint. To me, this bad means sticky, with a pronounced "notchiness" in its travel and a pronounced detent feeling in the dead center position. With the shaft lying horizontally, the detent effect is enough to keep the u-joint centered (against gravity) in one axis, but it will flop freely through its range of travel when the shaft is turned. Also, immediately upon first picking up the driveshaft and without being asked to check the U-joint, the machinist that pressed on my bearing asked me what was my plan for the bad U-joint, so there's a second opinion. So, I'm looking for a place that repairs u-joints and found Driveline Service of Portland - specialists in Mercedes driveshafts. Does anybody have any experience with these guys? Their website (http://www.driveshafts.com) tells a convincing story with key words like reasonable and proprietary process - at least it looks good to me. I'm waiting for a quote on one of their rebuilt driveshafts.

Any other favored options for u-joint rework on a 126?
Thanks, Big Mac

Bill:
Perhaps I'm using the wrong terminology, but job 41-100 on the 126 CD Rom shows what I'm talking about - there is a "U-joint", the permanent staked-in type, in the rear section of my driveshaft. It is just aft of the center support bearing, which is in turn just aft of the splines that slide into the forward section od the shaft. The lack of conventional circlip retention is what makes these U-joints a problem - shaft replacement is the high dollar conventional wisdom. That's what makes Portland's approach attractive to my thinking. The hard rubber flex discs on the ends of the driveshaft (bolt to the trans output and diff input) are OK. The car had a factory rebuilt tranny put in about 50K miles ago, and it looks like the flex discs were changed then. Hope we are on the same page now, and I appreciate the follow up. Big Mac

I'm not an engineer, but I love an elegant technical solution, especially one that can save money and simplify future maintenance. It sounds like their program exchanges entire driveshaft assemblies; I would prefer to send them my rear section only and have them put their slick U-joint in it. Will advise when I get the quote. Thanks, Mack

Big Mac... What did you discover about the shop in Portland? I have what I think is an IDENTICAL issue with my 190E, and owuld like to get it repaired, rather than simply replacing the Hi-$$$ parts...

Would appreciate your re-posting a reply...

Big Mac,

Don't know about your driveshaft but it sounds a lot like my 123 Model and if you dissassemble the two ends, you'd better mark them so that you can get them back in balance when you reassemble. Otherwise send the whole thing in for a complete while rebuilt.
Ben

ob1jeeper:
I have just been too busy to pursue repairs of the bad ujoint. I did get a call back from Driveline Service of Portland with an estimate of about $550, as I recall, for an exchange shaft. My son drives the 126 only a few miles daily, so I think I have some time before things get critical. I also found a local San Diego area shop, Oceanside Driveline, that rebuilds MB ujoints - I think in house. They tell me they can do it for about $300, with a one day turn around - I will go check them out. Another local outfit, Fleet Driveline service, says they can have an exchange shaft for me in one day for $276 - but I don't know where they are getting the shaft from, if it is a complete balanced unit, etc. It's nice to have local options! I think a new ujoint will fix the low frequency vibration, but the "white noise" is coming from further back - I just wish I could pinpoint the source. I intend to throw rebuilt axles at it first, since I can't replace the boots myself and I'm convinced they will crack through and leak pretty soon. After that it will be down to wheel bearings and the differential, which frankly seem more likely white noise generators anyway. We'll see - but it will be a while. Thanks, Big Mac

Bigmac,

I referred another MBZ owner to J.C. Whitney website, awhile back as they have a split boot cover for the MBZ. Runs about $15.00. Asked him to post a thread if he goes that way so we can all gain from his experience.

Ben

I would be interested to see the follow-up on this string. I get a random ringing clunk from my 81 300TD in lulls between transmission shift transitions usually at low speed down shifts. I also get a high ringing sustained squeak from the center bearing area that I hear only at low speeds with the window open - reflecting off the curbs and cars in a tight street. The clunk sounds and feels exactly like bad u-joints that I could easily fix in the various early 50s chevies I used to have as a kid. The ringing squeak sounds alittle like a wheel bearing but the fronts were recently packed, and it does not have the wowing sound I associate with that. Inspection shows only that I have about 1/8 inch play at most in the shaft at the center bearing. The U-joint looks solid as a rock but who knows? I have 178K on the car and the drive shaft has never been touched although I did a a half shaft to cure a rotating clunk there. Do my symptoms sound familar to Big Mac or Txbill? Any sage advice more than welcome before I get into this. Thanks

BigMac,

I got one from Fleet here in Columbia. It was a rebuilt shaft and was properly balanced. Actually, I had my original drive shaft redone by an Atlanta company and they did not rebuild the universal joint correctly so I had a slight vibration. After much trouble shooting, I figured that out and exchanged it for one from Fleet. The Fleet shaft works fine.

Cost $260 with exchange. New center bearing came with it. I thought that was a very good price.

Nic
'85 300CD

GREAT NEWS... My driveline vibration (1985 - 190E) was corrected by the replacement of the center carrier bearing. Even though the bearing felt reasonably good (manually spinning it when it was out of the car), it was the cheapest driveshaft part to replace, so it was the first to get the heave-ho... Voila!!! (thank goodness...)

Good luck with yours ...

The split joint covers from J.C. Whitney aren't worth a damn in my opinion. The ones I used cracked open at the split bond in less than 3000 miles. I wouldn't use them again.

The material used in them was much harder than the rubber
MB boots and it appeared there was too much stress in them and the bonded joint opened. That was my experience with them.

P E H