I am replacing the flex discs, center support bearing and transmission output shaft seal on my car due to the seal leaking and cracks in the rear flex disc. Is there any reason that using a used driveshaft with a univeral joint that is slightly notchy in one direction but far better than the one I took off the car is a problem? I know it won't be perfect but I am sure most of the ones driving around are probably similar and nobody notices. Shops pretty much just say "yeah, we won't touch that, unless you are wealthy I'd suggest you scrap it because Mercedes are expensive to maintain".

If you are on a tight budget you can just install it and see what happens.

pay attention to the markings on the driveshafts. Make sure the 2 driveshaft pieces are from the same car (don't mix and match the two)

A rebuilt driveshaft is $350-$400 (includes shipping)

The extra one I have I marked when I took it out, the one from the car had factory markings that lined up correctly. It looks more like $500+ for a 300SDL driveshaft, I could get one if I had to but the car has a bad head gasket too and I just wanted to fix it so I could drive it to work one day a week while I fix my other car. Once I fix the head gasket I would be more excited about spending another $500 on it.

if your 300SDL has a #14 head it's a good idea to have it checked for cracks when you're doing the head gasket.


What went wrong with the gasket?

I have a #22 head that should be good with some expensive work (remove prechambers and resurface) so that shouldn't be a big deal. It started pressurizing the cooling system enough to push coolant out the upper seam of the radiator and spray everywhere when you take the cap off the reservoir even after it sits for days. I don't know exactly what is wrong or really have the skill to confirm it, but it seems to match other peoples description of a cracked head or blown head gasket and it would be cheaper to replace the head than to have a shop actually diagnose it when that's probably what it is anyway. I didn't overheat it while I had it (I drove it everyday for a year) but it was pretty badly abused before I got it so who knows what may have happened previously.

X2 if on a budget, try it. Be certain to keep the halves together.

Good luck!!!

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

Depending on how notchy the U-joint is, it may or may not be an issue. If it's tight enough, expect some vibration above 50mph. I used a place out of San Antonio that was a driveshaft specialist. Was under $400 for my SDL including freight. I wouldn't waste my money until I knew the engine was fixed though.

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Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

The U joint on the one I am planning to use is far better than the one I took off the car, and I didn't notice any vibration before so maybe it will be OK. I mainly wanted to do the job to avoid having a flex disc break while driving (the rear one was cracked pretty bad) and to hopefully get it to leak less transmission fluid. I called the closest driveshaft place to me (still an hour away) and they said they don't replace staked U joints anymore. If I needed a new one I would probably just order one, the next closest places would likely mean taking a day off work to drop it off, and another day to pick it up. I definitely want to fix the engine first though, but for now it still runs fine. I'd only end up driving it 40 miles a week for a couple months at most before being able to fix whatever else I need to anyway.