PeachParts Mercedes-Benz Forum - Drive shaft tore off! flex joint disaster.

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Drive shaft tore off! flex joint disaster.

My girlfriend was driving her '78 240D and the drive shaft tore off the manual transmission at about 30 mph. It ripped two shift rods off the shift linkage broke the spedo cable and bend the cross member a little. That's all I could see so far until I get it jacked up. The tail shaft and rear housing seemed ok.

There was no noise or anything to warn us something was wrong.

I didn't know that those joints could just fail like that but I do now.

I think I can fix it for her if I can find new shift linkage rods.

Can anyone tell me where I can get a set of shift linkage rods for a resonable price?

Thanks,
T.

Here are links that cover the issue.

Bad flex disk driving home
Bad flex disk driving home - PeachParts Mercedes ShopForum

Bad Flex Disc
Bad Flex Disc - PeachParts Mercedes ShopForum

Weekend Wrenching (a great picture of a bad flex disc)
http://www.peachparts.com/shopforum/showthread.php?t=216701

The Death of a Flex Disc ... did I kill my 240D?
The Death of a Flex Disc ... did I kill my 240D? - PeachParts Mercedes ShopForum

What happens when you ignore that "little" driveline vibration!
What happens when you ignore that "little" driveline vibration! - PeachParts Mercedes ShopForum

Pay attention to your car!
http://www.peachparts.com/shopforum/diesel-discussion/320769-pay-attention-your-car.html

Flex Disc Orientation, safety and durability issue.
Flex Disc Orientation, safety and durability issue. - PeachParts Mercedes ShopForum

If your W123 is shaking down the highway. . .
If your W123 is shaking down the highway. . . - PeachParts Mercedes ShopForum

Correct way to install front driveshaft guibo? (FLEX DISC)
Correct way to install front driveshaft guibo? - PeachParts Mercedes ShopForum

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More data needed

Quote:

Originally Posted by chevy43 (Post 3027447)

I need VIN# and pictures to build a parts list:
* Driver side transmission lever arms area.
* Any damage to the bottom of the main shifter assembly.
* Drive shaft damage.
* Drive shaft carrier bearing BOOT damage.

.

Can I remove the shifter out the top to inspect it?

Tonight, I found one shifter rod on the side of the road where it all happend. I don't know how bent it is and the yoke is busted off the end - but at least I found one.

I will get some pictures when I get the car jacked up.

Thanks!
Treven

Here is another bad disk picture.

http://www.peachparts.com/shopforum/diesel-discussion/326818-worst-flex-disc-competition.html

where are you located on the central coast?

Charlie

Charlie,

I'm in Santa Cruz near Kellys Bakery. I have an '82 Datsun King cab diesel too!! Let's get together sometime.

I'll give older mecedes more room on the freeway in the future!

I bet lots of them out there have not been inspected.

Would have been nice if Mercedes had put a driveshaft loop under there.

Beter yet would have been a normal U joint.

Mine is not real bad but has the telltale cracks.

With an Auto Trans and my bad Eyes it was hard to inspect the one up Front without dropping the bolted up Cross Member so there is a lot of room to look at it.
However, I knew the rear Disc was cracked so they were both getting replaced anyway. Both had cracks.

Don't forget to check the Bushings on each end that center them.

I hope they come with new bushings 'cause I'm pretty sure those are all in the ditch on the side of the road.

Quote:

Originally Posted by chevy43 (Post 3027918)

I hope they come with new bushings 'cause I'm pretty sure those are all in the ditch on the side of the road.

Pic of the Drive shaft Bushing.
It does not come with the Flex Discs Kit.

There is one pressed into each end of the Drive Shaft. The good ones cost around $60 the aftermarket ones like URO type ones around $20.
I did not need to change mine but they are soupposed to be packed inside with Grease. Mine were dry and needed to be re-packed.

If the Drive Shaft Bushing is worn off center or damaged I am guessing it should be replaced.

The Pins that stick into Bushing End that is not pressed into the Drive Shaft also ought to be inspected.

Here are a couple of pictures if they work:

One of the ears on the transmission flange is a little bent. The center seems to run true.
I think I can straighten that cold....

The shift rods are bent and broken.

The cross member is a little bent up but if removed, can probably be hammered straight.

The shifter levers sticking down into the tunnlel are bent a little but should straighten

The tail housing casting isn't broken.

Spedo cable housing wrecked.

Hopfully the transmission gears didn't get hurt by the violent jerks on the shift rods.

I just checked on the Pick and Pull webb site and these are the only 240D`s in the yards.

Pick-n-Pull » Check Inventory

Doesn`t tell you if it is an auto or manual trans though. I know 2 in the Windsor yard are manual form another member that was there.

I know W123 77 to 80 use the 2 piece (seperate bell Housing) Iron Box transmission like your 78 uses. not sure of the 81, but know 82 & 83 use the one piece Aluminum trans. the shift rods from this trans will not work on the Iron Box trans.

I do have a trans X mount and the shift rods for the older trans.

Does anyone know if the Tri Flange from an automatic (Diesel) will work on a manual trans? are the splines the same?

Good thing she was only going 30mph when it came apart, could have done some severe damage if going 65 on the FW.

I had to look up kelly`s Bakery to see where it is, I don`t go on that side of town very often. generaly get as far as Costco.

Charlie

Wow!
Thank you for your reasearch and help.

Any advice on removing the drive flange off the transmission?

The nut looks special.

I think if you just start pulling off the damaged stuff you may well find the tri flange is not damaged. In fact the damage looks pretty minimal to me. Get all that frayed flex disc out of there and it will look a lot better.

The three fasteners for the flex disc are just through bolts and not at all special.

Quote:

Originally Posted by chevy43 (Post 3028138)

Wow!
Thank you for your reasearch and help.

Any advice on removing the drive flange off the transmission?

The nut looks special.

you likely have the slotted nut, you can put two common screwdrivers together with a hoseclamp, and pry on them. or use the screwdriver/hammer method to remove the nut. you will need a new nut, and it's going to be a 30mm 12point head.

Quote:

Originally Posted by chevy43 (Post 3028138)

Wow!
Thank you for your reasearch and help.

Any advice on removing the drive flange off the transmission?

The nut looks special.

You are welcome.

Any update or new pictures?

.

Any update on this? I've had the same issue and am looking for safe ways to remove the nut.

Quote:

Originally Posted by chevy43 (Post 3028138)

Wow!
Thank you for your reasearch and help.

Any advice on removing the drive flange off the transmission?

The nut looks special.

Anthing that was bent should be replaced.

Somepeople had the special Sockets for that slotted Nuts in the Tool Rental, I have not paid attention to which ones are which.
Tool Rental List
http://www.peachparts.com/shopforum/showthread.php?t=291660

Transmission tools Don't know anything about this site that I copied from another forum.
http://www.specialtyautotoolrentals.com/index.php?cPath=25&osCsid=aahug5li7mnc31dfjhl0rp3rn0

PM Stretch for details on this: In another forum I believe He said that the Replcement Nuts are 12 Point and use a regular Socket. He said it is possible to use a Punch and knock and loosen the Slotted Nut and then replace that Nut with the New 12 Point Nut and avoid buying the special Socket.
I think that may or may not work.

If you are going to use the Punch method I would be sure that you have a source of the 12 point replacement nut first.

Thank you, the 12 point replacement nut is the last thing I need to make this come together.

I appreciate your research and advise.

Think you've seen it all? How's this for a flex disk disaster:

http://www-nass.nhtsa.dot.gov/bin/Airmis.exe/getPDF?AirMisid=278031626

Quote:

Originally Posted by Mxfrank (Post 3350809)

Think you've seen it all? How's this for a flex disk disaster:

http://www-nass.nhtsa.dot.gov/bin/Airmis.exe/getPDF?AirMisid=278031626

Now thats friggin interesting. After doing the 5spd swap the no name brand flex disk I installed lasted 14,500 miles before it started making a ticking sound. There was no vibration, just very light metalic tick tick tick under hard acceleration. I replaced it promptly with Lemforder/SGF part. Keep in mind that I'm using smaller flex disks than what came originally on the 300D turbo.
http://i.imgur.com/GqYOlYJ.jpg?1

Quote:

Originally Posted by Mxfrank (Post 3350809)

Think you've seen it all? How's this for a flex disk disaster:

http://www-nass.nhtsa.dot.gov/bin/Airmis.exe/getPDF?AirMisid=278031626

Did you notice that car was only 6ish years old but had 202k miles on it already? :eek: That's well over 30k a year....sounds like they did not maintain the car properly. That flex disc's rubber looked very dry and baked like it spend a lot of time in a really hot/dry climate. Not surprising it failed under those circumstances.

I've hit a snag here, I never altered the nut to loosen the front of the driveshaft when I removed the flex disk. Now it seems as if there is tons of room between the transmission yolk and the flexdisk.

I must be missing something?

Could the centering bushing also be shot? Thank you for all your help.

I should also add, I am able to slide the front portion of the driveshaft in and out a small amount, just enough to be able to get it on the transmission. Thank you again.