Driveshaft U-Joint Failure

[Douglas]

Someone mentioned a vibration in his or her driveshaft at speed (Trice?), so I thought it was worthwhile to start a thread on universal joint replacement.

I'm talking about the end of the driveshaft where it meets the rear end. I know the u-joint can go bad after awhile.

My question is what are the symptoms of impending failure, if any?

Douglas Kim
New York, NY
280 SL #016220

[mdsalemi]

What precedes failure of a U-Joint or drive line? Funny noises.  My entire driveshaft exploded where it attaches to the transmission.  Destroyed the transmission, rendered the driveshaft and all of its components useless.  Parts of both are probably still scattered in the ravine off of US127 in Mt. Pleasant, Michigan.

For several days prior there were some funny noises--klunks, rattles and what have you that I could not put my finger on but because of my lack of experience with the freshly restored car, I had no idea whether they were normal or not.  We don't know what happened or why, but suspect was that some bolts where the driveline attached to the transmission were not tightened properly and "let loose" while accelerating through 60 MPH as I was getting on the highway.

Doug, you asked about "U-Joint Replacement" and to that end I strongly suggest that those interested go to the link below, and drill down on their site to Mercedes Drivelines.  A good description of our drivelines can be found there; it's too long to repeat here.

I stand by those that have helped me, thus comes the shameless plug for Driveline Service of Portland (Oregon). You can find this firm at:

http://www.driveshafts.com/

Anybody wanting to advance their knowledge of our Mercedes driveshafts should contact these people.  When I needed a new driveline (wobbly U-Joint), I called them on my wireless phone right from the shop; ordered the remanufactured driveline in a matter of minutes; three days later it arrived and the old one was put back in their reusable crate, sent back to them, and all was well.  I suspect that it was not a failure of their product but rather due to those who serviced the transmission.  So, I've done this driveline exercise TWICE and hopefully for the last time.

A visit to their website will tell you a lot about drivelines.

Michael Salemi
1969 280SL
Signal Red w/Black Leather
Restored

[George Davis]

I can't add a lot to what Michael said, but as I understand it, the u-joints are replacable in the 230 driveshaft but not in the 280 driveshaft (they are staked in place on the 280).  I don't know where the 250 falls.  But either way, if repair is required, I suggest sending it to a driveline shop that does these driveshafts.  This way you get quality u-joints and a properly balanced assembly.  Driveline Service is good and I also recommend them, but there are a couple others in other parts of the country as well.

Regarding Mike's d/s explosion, it is my opinion and practice to ALWAYS replace the flex disk and the bolts and nuts that hold it to the trans flange and driveshaft with new whenever the bolts are loosened.  This is not cheap, but it's a lot cheaper than a replacement driveshaft and/or trans flange.  If those bolts are even slightly loose, they chew up one or both flanges.  You may think they're tight, but I believe the metal sleeves crush slightly, so the bolts can still wiggle enough to cause damage even though they feel tight.  I learned this the hard way, 'though not as spectacularly as Michael did.

George Davis
'69 280 SL Euro manual

[rwmastel]

quote:Originally posted by George Davis

Regarding Mike's d/s explosion, it is my opinion and practice to ALWAYS replace the flex disk and the bolts and nuts that hold it to the trans flange and driveshaft with new whenever the bolts are loosened.

George,
I believe there is a right way and a wrong way to install the flex disk, perhaps this is what happened in Michael's case?  Always RTFM.

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

[mdsalemi]

quote:Originally posted by rwmastel

quote:Originally posted by George Davis

Regarding Mike's d/s explosion, it is my opinion and practice to ALWAYS replace the flex disk and the bolts and nuts that hold it to the trans flange and driveshaft with new whenever the bolts are loosened.

George,
I believe there is a right way and a wrong way to install the flex disk, perhaps this is what happened in Michael's case?  Always RTFM.

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

Ahh, Gents,

Good info, all of it.  The destruction was too great to try and determine the source of the failure, barring a NASA like investigation.  The car had just received a new main seal on the transmission, so the trans had been recently removed.  Then the car went back to the restorer for a "punch list" of items to be corrected, who knows what happened there.  Both places were professionals, but even they make mistakes.  It was within 100 miles of picking up from the restorer after the punch list and after the main seal change when the failure occured.  The bottom line was I had been through the driveshaft exercise twice in a year!  I can assure Doug that those noises are etched into my brain's memory and should I hear them again, I'd pull over in a heartbeat.  I would suspect that most of our members have their original driveshaft, or if not, perhaps they've done a once in a lifetime change.  When the damaged driveshaft was sent back to Driveline Service they said it was too badly mangled to rebuild, thus no core charge would be refunded!  After the sad story, they decided I had had enough grief and did indeed give me a refund.  But I am SOOOO past that now...


Michael Salemi
1969 280SL
Signal Red w/Black Leather
Restored

[hands_aus]

As part of the recent rear axle rebuild on my 250sl, both of the universal joints were replaced along with replacing the centre bearing and rubber bearing bush.

A new MB flex disk was added and then the whole unit was balanced before being re-installed in the car.

George is right about the flex disks being expensive ($545.00 AUD).

Bob Smith (Brisbane,Australia)
RHD,1967 early 250 SL, auto

[Vince Canepa]

I did my driveshaft "overhaul" myself, but I have access to a press.  One thing to remember, the circlips that hold the u-joint cups in place come in different thicknesses.  Too thick a clip and the u-joint will bind.  Too thin a clip and the u-joint might not be centered with respect to the axis of the shaft itself.  If you are not a skilled DIYer with good tools, send the shaft to an expert.

Vince Canepa
1967 250SL
113.043-10-001543
568H Signal Red
116 Caviar MB-Tex