Hello All!

'83 300SD 154K

I replaced the flex disks and center bearing and found the U-Joint has a "hitch" in it. I'm going to replace the drive shaft and it would be much easier if the exhaust is out of the way.

What is the best way to move the exhaust out of the way? Will the front flex pipe bend enough and let me just "drop the exhaust"? Do I need to cut the bolts and take the system apart after the front pipe? Advice please.

Thank you!

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Richard
'83 300SD 180k
'87 300SDL "200k"
Central Ohio

Not familiar with the SDs but on the 300D there is a 2-bolt flange connector right after the flex/header pipe. That would be a good place to unbolt and separate the pipe.

On the driveshaft, have you found a place to get it. Not sure yet if I will need one but I am in the process of doing exactly what you are doing...removing the ds to replace the center support bushing and bearing. I have not successfully dropped the ds yet so I can't say the condition of my u-joint.

Prices seem to be around $350 on up plus $60-$75 for core.

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Thanks - I know that connection in the exhaust system and I'll just get a new seal and bolts since they are very rusty - I've learned to quickly try to take off the bolts but if there is any resistance get out the torch .

All of my searches for drive shafts are in that $350 range except one.

http://www.thrashdriveshaft.com/import2.htm#MERCEDES

Average Price is $345 plus $60 core.

http://www.wholesaleimportparts.com/driveshaft_catalog.php?make=Mercedes%20Driveshaft

Price $317 plus $60 core.

http://www.driveshafts.com/pages/mercedes.html

Replacable U-Joint but must be greased - price is around $350

I can't get one to pull up on Fast Lane.

I'm toying with the idea of trying the one with the U-Joint that must be greased. It is a lot more maintenance (supposed to get a shot of grease every 5K miles) but when it comes time to replace the U-Joint again, the replacement is only $25. This would not be worth the trouble to most verus the no maintenance drive shaft, but I am driving 30-35K miles each year and I believe my U-Joint was bad when I bought the car with 125K on it. So - in 4 years instead of forking out another $350 it will just be a quick U-Joint change like we used to have to do on American RWD cars. Thoughts?

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Richard
'83 300SD 180k
'87 300SDL "200k"
Central Ohio

Recently pulled the driveshaft out of the '86 in a valiant attempt to cure it's ongoing vibration problem. The exhaust can remain in place. The flex discs are separated, the center support is removed and the driveshaft will snake it's way out of the vehicle without too much difficulty. It bends nicely in the center via the U-joint.

Might have to do the whole job again and chase the u-joint this time.

My question as to the replaceable, Does it need rebalancing after replacement? How do you insure that the front and rear shafts line up again, or does replaceable mean that you send it back to factory.

The Portland people do have an interesting write up on MB drive shafts that I encourage all to read driveshafts...mercedes_ujoint

The driveline folks in San Antonio have excellent customer service. I could not get my new driveshaft to loosen at the spline fitting. It must collapse for installation. They air freighted me a new one overnight. The driveshafts they use are actually from SanDiego, and the expense was all on their end.

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Thank you Brian! That will save me some work. When I removed the driveshaft I left the flex discs attached to the driveshaft and didn't even thing about taking them off I snaked the driveshaft out by splitting it.

How many miles are on the '86?

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Richard
'83 300SD 180k
'87 300SDL "200k"
Central Ohio

The clock reads 135K.........but, I've got reasonable doubt about the accuracy.........for various reasons.

I think in the perfect world you would have the driveshaft rebalanced after any kind of change. My experience has been that the only time I have had to rebalance a driveshaft after replacing a U-Joint is when I forgot to mark the driveshaft parts so I could put them back together in their "balanced" position . I think you can get by without the rebalancing because the U-Joint is a small, compact, precision part that is fairly uniform.

The way I'm looking at this is the max I can be out if the replacable U-Joint does not work is $85. $25 for the new U-Joint and the $60 core charge that I won't be able to get back from ordering a "normal" rebuilt driveshaft since I doubt they would take back my modified driveshaft. If it works I will save close to $300. There is also a risk that the Portland shop will go out of business and I won't be able to get the special replacement joint.

The real pain is going to be crawling under the car every 5K miles, take off the shield under the car covering the center of the driveshaft, pumping some grease into the joint and installing the cover again. Maybe I can get another shield and modify it with some kind of simple-to-remove door or panel just big enough to gain access to the grease fitting.

As for lining up the driveshaft halves in the benz - all I did was use whiteout to mark the splines through one of the "splits" in the driveshaft. That little brush was perfect for doing that.

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Richard
'83 300SD 180k
'87 300SDL "200k"
Central Ohio

Thanks Brian. I'm trying to figure out if my driveshaft U-Joint wore out prematurely because I don't see many references to having to replace driveshafts in the forum.

Mine is bad enough at 150K that the "hitch" in the U-Joint holds the short shaft piece in position and I know the vibration was there when I bought the car at 125K (either that or I have an oversensitive vibration sensing butt )

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Richard
'83 300SD 180k
'87 300SDL "200k"
Central Ohio

What's the characteristic of the vibration? What engine speeds so you notice it and under what loads do you feel it.

I'm very sensitive to it myself.........I'm sure it's present at all speeds to some degree, but, the road irregularities and the slight tire unbalance will mask it at most speeds.

Hey Brian,

The noise and vibration - I would say it is a low frequency resonant type of sound that pulsates a little and can be heard at 60 and 70 mph, which is very irritating since that is speed limit +5 for the highways in Ohio. The vibration can also be seen as a slight fuzzing of the reflection in the mirrors. I'm sure it is there at other speeds but not loud enough at lower speeds and the ROAR of the engine at 80+ makes it hard to hear it. It is also loudest at steady cruise but that may also be because of engine noise.

I just ordered the driveshaft with the replacable U-Joint. $355 plus $75 Core shipping both ways included. I asked how important it was to grease the joint at the "recommended" 5K interval and he said they used a very good grease that should last much longer than 5K miles since they assume people will forget to lube the joint. He would not tell me what they used (I hate that!). He said to use any good U-Joint grease. Any recommendations?

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Richard
'83 300SD 180k
'87 300SDL "200k"
Central Ohio