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I noticed some cracks in the rear one and decided to replace the front and rear flex discs. I did this at the same time as shimming down the center support per the other thread (which I now think is to compensate for transmission support sag and keep everything at the right angles).
Replacement is fairly simple. I got to try out my new power ratchet which turned out to be the perfect tool for the job. T60 and 18mm open is all you need. Oh, and a decent pry bar to free the disc from the flanges.
But this thread is really a PSA about part compatibility. Unfortunately I put my faith fully in FCP Euro without doing enough independent research before ordering.
It is the only flex disc that FCP carries for our cars, and according to the Q&A section, the front and rear are the same. So I ordered two.
First the good news: other than bending the front heat shield out of the way, this was pretty easy work. Just be careful when prying but it will eventually pop free. It is also a little tricky to slide the driveshaft out of the way enough to pull the discs out. Loosen the center support bolts to let that slide around a bit. My front disc perfectly matched the parts I bought from FCP Euro and the Mercedes part number compatibility agrees. Also, be prepared for the transmission to be in neutral for a while which requires ignition on. Consider your battery state of charge....
The bad news: it does NOT match the rear. You can see the design of the disc is also different.
Front disc:
Rear disc:
The hardware used in the rear is different lengths and two of them have a very large flange head. Unfortunately I kept going with the install, still trusting FCP Euro. I figured, hey, this is aftermarket so things may not look identical to OEM but if it physically installs then I guess I'll roll with it. So I tried that and it did install. It actually seemed fine. I did the front one next and since that one was the same I was thinking everything is good now. Until I looked at the center support. It was now slid all the way back in the adjustment slot and possibly wanted to go further. Why? Because the replacement rear disc is thinner (due to not having those wide sleeves) and this pulled the rear section of the driveshaft rearward.
Well, I torqued everything anyway. I was able to rotate the driveshaft by hand (in neutral). Since it wasn't visibly binding or making noise I thought the next step would be to test drive. My thought was if something sounds or feels wrong as I back the car out of the garage, I will stop immediately. Well, it was fine. In fact, the NVH I was experiencing seemed to be gone. I took the car up to 100 and it definitely seemed smoother than before. Yay? Not so fast.
I was still bothered by the difference, knowing the sleeves don't engage nearly as much as the original did, plus the out of position center support. Ended up looking into it and wouldn't you know, the P/N for the rear is different than the front (although EPC has no drawing of the part which adds to the confusion). Gee, if only I had taken the 20 seconds to look at this originally.
To be clear, the correct P/N for the front is: 000-411-06-00
The correct P/N for the rear is: 000-411-10-00
Notice it only shows 07-10 W221 compatibility. So yeah they need to fix their catalog. In the meantime I am not going to drive the car. I am worried about putting stress on the center support bearing or isolator. The fact that it felt fine (or even improved) on my road test suggests I probably didn't hurt anything but I wouldn't want to run it like that long term. I'll update the thread when FCP Euro decides what they want to do for me. Somehow the right part needs to get on the rear, I just don't know if they'll want the other one back (I don't see why), or what they might make me pay for the correct one (it is a bit more expensive). I could also just ask for a refund and buy the OEM for $250...
Nice write up on the flex discs surely a road we'll all cross at some point with these 212s. Sorry if I missed it on mobile . Any further info on the center support shim ? mercedes have a part # for this . Are there any symptoms to look for to indicate a shim is needed ?
It would have been ideal to road test the car after just doing the 2.5mm shims (you want 8mm stainless fender washers) as that may have helped all by itself. But my rear disc was definitely cracked. The front one somehow looks worse (peeling) but I didn't really see any cracking. I can look again.
I am preparing to do this on my W212 as well, my biggest concern is being able to slide back the driveshaft to get the discs off and on once I get under the car. You mentioned loosening the center support, were you able to do that without dropping the exhaust? In the photos the center support looks like it's behind the exhaust and heat shields.
Center support bolts are accessible with everything in place. You will need to put some muscle into sliding the driveshaft forward (for the rear) or backward (for the front). The front has a sliding spline. The rear seems to be fixed to the center support. I was able to do everything without dropping any heat shields or exhaust. Getting the rear flex disc out was tight and installing the correct one will be tight as well.
FCP Euro is sending that Febi Bilstein unit (which they say crosses to 000-411-10-00). Should get it tomorrow. They want the wrong one back and already sent a shipping label. So, this seems to be going well so far.
I received the correct part (Febi Bilstein) yesterday. Removed the wrong one from the rear, and installed the correct one. It is definitely a snug fit to R&R these but possible so just be patient and work it.
The correct flex disc for the rear (this one by Febi Bilstein)
Happy center support
For the rear there are four long bolts and four shorter bolts. Two of the longer bolts use a large flange head which seems to capture the damper. The replacement bolts don't have this style. These don't seem to be a TTY application (just 50 lb-ft) so I felt comfortable reusing the two. The other six I did use the new bolts that came with the new disc.
As shown my center support is now back in range, so I'm happy. Road test is actually the same as it was with the incorrect part. I think the only NVH left is tire noise. What I don't know is what changes I am experiencing from the new discs and what changes are from shimming the center support down 2.5mm. In any event I think this is a good maintenance action if you see any kind of cracking in your rubber flex couplers.
FCP Euro sent me a FedEx return label so the wrong part is on its way back to them. They didn't seem to charge me for the more expensive Febi Bilstein part which I guess is good, though I am not sure about warranty registration....I'll deal with that at some point. Or maybe I won't, because these should last 8 more years I would think.
I received the correct part (Febi Bilstein) yesterday. Removed the wrong one from the rear, and installed the correct one. It is definitely a snug fit to R&R these but possible so just be patient and work it.
The correct flex disc for the rear (this one by Febi Bilstein)
Happy center support
For the rear there are four long bolts and four shorter bolts. Two of the longer bolts use a large flange head which seems to capture the damper. The replacement bolts don't have this style. These don't seem to be a TTY application (just 50 lb-ft) so I felt comfortable reusing the two. The other six I did use the new bolts that came with the new disc.
As shown my center support is now back in range, so I'm happy. Road test is actually the same as it was with the incorrect part. I think the only NVH left is tire noise. What I don't know is what changes I am experiencing from the new discs and what changes are from shimming the center support down 2.5mm. In any event I think this is a good maintenance action if you see any kind of cracking in your rubber flex couplers.
FCP Euro sent me a FedEx return label so the wrong part is on its way back to them. They didn't seem to charge me for the more expensive Febi Bilstein part which I guess is good, though I am not sure about warranty registration....I'll deal with that at some point. Or maybe I won't, because these should last 8 more years I would think.
Was under mine this past weekend . @ 94k my rear is cracked . Nothing of significance but I will order up both flex discs for sure . Worth it to install the center support shims if I didn't have any symptoms prior ? Sorry if I overlooked it above - what size washers did you end up using ?
If you have no symptoms I guess leave the shims out. You can install them whenever you want. Of course, you will be loosening the center support bolts to do the flex couplers but it's hardly a lot of rework (other than lifting the car up again).
If you do choose to run the shims, you want something about 2.5mm and the ideal spec would be 8mm stainless fender washers (Ace Hardware carries them where I live). They were out of 8mm so I used 10mm.
The correct way to deal with the shims is to measure the driveshaft angle but I decided that science project was not worth it.
Thanks for the torque specs above , did both flex discs yesterday . Car is noticeably smoother , both discs had quite a few cracks when flexed by hand . Bought them from mb & one of the techs said they put green wheel bearing grease in the sleeves on both ends of the driveshaft. What that's worth I don't know , but I bought a tube & did it while the driveshaft was popped off both ends.
Last edited by SilverE5588; 07-17-2023 at 01:54 PM.
Finished this job on the rear flex disc last weekend, a few notes below from doing this on my 2011 E63. I'm not a mechanic or professional, the items below are for reference only.
I put the car in neutral with the key in position 2. I was able to move it back to position 1 and leave the key in the ignition to keep it in neutral. Saves some battery power over keeping the ignition on all the time.
I had to completely remove the screws holding the center support bearing to the body to push the driveshaft far enough forward to get the old disc out and the new one in. This probably also saves the center support bearing from any excess stress.
I cleaned and added new grease to the driveshaft end bearing before putting it back in the differential.
AMGs seem to have an additional flexible disc on the end of the driveshaft. Not sure about the lifespan on it, but mine looked ok. It seems like the flex disc takes most of the stress
The additional disc on the end of the driveshaft does make prying the flex disc off more difficult since it does not provide a solid surface to work against. I had the best luck with prying the disc off the differential, moving the driveline forward to get extra space, then holding a small prybar near the center of the driveshaft to stretch the flex disc off.
Part number for the rear disc on my car is 0004110800. The Meyle HD part from FCP Euro seems to be an exact replacement.
My car also had two wide headed bolts that I had to reuse since they were not included in the kit. Also, only 4 new nuts were included for some reason, so I bought 4 more from the dealer\
At 91k miles, what I presume is the original flex disc was very badly cracked.
All done:
Last edited by ponia003; 07-19-2023 at 10:38 AM.
Reason: Image alignment
That extra thing on the rear of the driveshaft is probably a damper. I did pry against it to an extent but didn't seem to damage it. That was also part of my thought with reusing the very large headed bolts. They help locate the damper though they don't really touch it (it is very close).
06-25-2023, 09:26 AM
