The car: 1981 240D Manual

The symptom: A week or so as I was driving along a loud bang as something flew into the drive tunnel. No symptoms for a few days, but now about halfway through first and second gear, a tapping/knocking sound and vibration comes from the bottom of the car, right from the transmission tunnel. You can feel the thunk,thunk,thunk through the driver's seat. Its bad. once revs get high, the vibration, knock, thump goes away - usually by the middle of third gear.

This is obviously a driveline problem, and it developed quickly - over three or four days to the point that it is now loud enough that I have parked the car for fear of what it will do when this lets go.

I am going through the list of what this could be. Universal joint? Flex disc? bearing? Motor mount? What else is there between the engine and the rear end?

When I replaced the oil pan a few weeks ago I noticed that the motor mount it rests against was badly boogered and needed replacing. As its a $11 part, I'll replace it for sure. The car is now at the local wrenchtwister's (baby its cold outside - I'm not equipped to roll around on cold asphalt). Any ideas are appreciated.

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1981 240 D in the Toronto Area
Ivory with one black fender

You'll just need to get under there and look. You have a decent handle on what it could be.

You're pretty lucky your driveshaft didn't give out already. That sort of symptom should usually say "stop driving me"

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1979 300D 040 Black on Black - 1985 300D Maaco job (sadly sprayed over 199 Black Pearl Metallic) on Palamino

http://i.imgur.com/LslW733.jpg

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Visit the W123 page on iFixit for over 70 helpful DIY guides!

The first indication of a noise like you first heard, I would be stopping...NOW!!!!

Check out these images on Google of what can happen when one is badly cracked, coming apart and has come apart and the damage it can cause.

https://www.google.com/search?q=mercedes+bad+Flex+Disk&biw=948&bih=633&source=lnms&tbm=isch&sa=X&ei=oXhlVPyiJK-CigLw6oGQAw&ved=0CAgQ_AUoAw

Do not use the $11 part you mentioned. It is probably a URO Chicom part and has a short life span. Lemforder is a good brand or go the Dealer.


Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

center support bushing gave up on the first w123 as I was on Newport bridge a while back. Suddenly lots of banging from driveline tunnel. Scary loud. Luckily no shaft damage.

Made it off the bridge but towed home. Fresh bushing, bearing & flex disks were a reasonable expense & neither too difficult nor time consuming.

The weather was more agreeable though.

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1991 300D

If it turns out to be one of more Flex Discs be sure the Mechanic does not put on some made in PRC Flex Discs.

Card Board is good insulation to lay on and Harbor Freight sells some Foam Mats for walking on. Sort of antifatigue Mats.
I use at least one of the Mat Squares when I get under the Car.

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84 300D, 82 Volvo 244Gl Diesel

A few years ago I had the U-Joint replaced at a Drive Line shop. they replaced the Centering Bushing on the DL ends, Center Support and bearing. The U-Joint is a Ford joint as used in a Mustang and grease able with a Zerk.

made it to 33K miles and figured out the rumble kind of noise was the Support rubber giving out. It was torn just about the whole way around.

Ordered a new one from pelican...a Fibi with a made in China sticker. . we`ll see how long this one lasts.
I think an old used one off a MB junker in the yards would have been a better option. Next one will be a dealer item.


Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

Those mats works great for tool boxes as well. Cut out the shape of the tool and you'll keep track of tools. I actually
Need to get one of those mats to lay on

That is what we do at work. Keeps the assemblers from sending their tools out with the equipment. Not only is it the loss of the tool, but it could be deadly if it gets between the bus bars and the customer finds it when they go to turn it on.

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The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

Charlie - this is th emount on Peach Parts: http://www.pelicanparts.com/catalog/images/Connect-Images/1232400365-M36.jpg

From Febi it lists at $10.75 - is Febi a not reliable brand?? I thought they were OK and Uro was the one to avoid.

I found the Lemforder flex disk for $40 from Groton, so if my mechanic can't find a better price, I'll order from there. I think you need 2??? I'm sortof leaning to doing everything at once while the car is in the air. OTOH, I don't want to sink a crapload of money into this car - I'm not even sure I want to drive it until spring.

Depending on wrenchtwister rates, I may park it and find another ride until I can DIY this in May.

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1981 240 D in the Toronto Area
Ivory with one black fender

Prospector I just went thru all that with my 85 300 SD. I had to drop my entire drive shaft twice because I did not have all the parts I needed the first time. What it was on mine was shaft is connected with 6 bolts front and rear on the front 1 of the bolts loosened up and it elongated the hole in the metal yoke. I bought a used shaft, 2 new flex joints, new u-joint, 2 center bushings, 1 center carrier holder +bearing. Total cost for parts was about $ 150 + and a lot of hrs. labor. You could look up my posting on issue under my u.n. On mine I had to drop pan + exhaust to work on.

I would go to the dealer. at a minimum, to discover the correct part numbers for your car.

keep in mind, the front and rear flex discs are sometimes different.

if it's my car, I'm personally inspecting the carnage to find the issue, and PERSONALLY looking over the flex discs for ANY signs of impending doom...

if it's just the center bearing support, no big deal, change it, but also order a new shaft slide boot.

if it's the flex's, you need to change the diff end centering bearing, the discs, both front and rear.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

No this is the mount I mentioned I replaced.

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It all depends how long you are going to keep the vehicle. A short time, then throw the cheapest parts you can find at it, and move on. Let the guy you sell it to worry about it. Using good quality expensive parts will not make it worth any more money on resale. If you do decide you like the car and want to keep it long term, then I would be replacing the best parts I could find.
We that have been around these old MB`s are giving you the best advice from what we have read and experienced.
Taking your car to a local Wrench, will add up real fast $$$$, been there done that. But then Iam not laying in the Snow and cold either. Some times you do have to take them in, I try not to.




Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

This is a good one to revive. wait till you get to post#20 LOL

http://www.peachparts.com/shopforum/vintage-mercedes/205055-what-happens-when-you-ignore-little-driveline-vibration-2.html


Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

Yee Haw - I get to replace my driveline!

OK, it could be worse, but basically everything has let go. Looks like I'm replacing 2 flex discs, a centre bearing, and the front Yolk and seal.

Parts cost (from FCP Euro) is about $300, plus 4 hours labour... Merry Christmas.

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1981 240 D in the Toronto Area
Ivory with one black fender