When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Questions on my flex discs and shaft bearing job on my 2010 E350
Guys,
I’m doing my flex discs and shaft bearing on my 2010 E350. I’ve owned this car from about 2012 and don’t believe this stuff has been replaced yet because I’ve never done it. Here is the state of things upon disassembly:
as you can see the boot that was mentioned by some on a previous post is missing. Could my model just not have had this originally? It’s pretty cheap I don’t mind throwing one on if I can make it fit but just thought I’d ask.
Actually the only vibration was mostly at startup at idle that I diagnosed as engine mounts and I’m replacing those. I was previously told that I needed to replace the flex discs after an unrelated service appt with my dealer so I figured I’d replace those while the car is apart.
so the question I have is on the propeller shaft alignment sleeves. I’ve read in the service manual that these have a specific alignment depth, but the front sleeve in my car at this time is not at the recommended depth (approx 24mm vs 36.3 per the manual). So the questions I have are, do the alignment sleeves have to be replaced? Are they an actual wear item i.e. is it made of multiple parts with a rubber component or is it just a solid piece of metal? If they can and do wear how do I inspect them to determine this? If I do replace them, do I insert them to the same depth they’re at now or do I go by the service manual? Please see the pics for further clarification.
Ok so after taking a closer look at the propeller shaft alignment sleeves, these items do have a rubber component to them so they can, I presume, wear. Although I see a mention of these things in the service manual, I haven’t seen anyone mention them in posts here or on YouTube videos detailing changing the flex discs. Does anyone have any input on whether or not I need to worry about these? They seem to be in good shape but just not sure if changing them is opposed to be done when doing the discs. Thanks for any info you can share.
Boot - Looks like there was one installed at one point. Yes there should be a boot there to keep water out. The MB manual clearly mentions the boot when inspecting and installing.
Do you notice signs of the drive shaft being worked on previously, besides the missing boot?
I was scrolling thru eBay at used W212 drive shafts and they seem to all have boots. At least the ones im seeing. Though there are a few different part #'s.
For the centering sleeve I see a note in the removal instructions about the specified insertion dimension may deviate... Not sure what that means exactly. But, if it were me i would leave it alone.
I did notice on the diff side there looks like a more pronounced wear ring on the shaft where the transmission side looks even. I wonder if there is an issue with the angle of rear section of the drive shaft? I'm purely speculation and just wondering.
Thanks for the input Tim. Yes I agree the pin on my rear end looks rusty like there is little or no contact with the centering sleeve. Not sure what that means. I agree the boot is required and I have ordered one already. I ordered the centering sleeves for the car too. I’m also a little reluctant to replace the sleeves because of the discrepancy with the “a” measurement according to the manual of 36.3mm vs the actual measurement of 24mm on my front sleeve. I thought that I might have seen a service update that the centering sleeve “a” dimension was changed from the original measurement to a new measurement. Have you seen that too? If I decide to change the sleeves out I don’t want to install it incorrectly.
This was the change in the “a” measurement that I mentioned before that I recalled seeing somewhere. Looks like it came out prior to my model year 2010 so maybe mine wasn’t changed? But this still doesn’t explain the difference between the “a” measurement in my car and the manual. Thoughts?
I just saw those modification notes. Looks like they were update 9.2.09 and then 10.2.09.
So if your car was manufactured prior it could have the old specs.
I dont see anything saying the centering sleeves should be replaced if they dont have the current specs. Usually would be a TSB and i'm not finding anything about it.
If you do replace them i'd use the specs you posted. I'm assuming you have the 212.056?
Yes it’s the 212.056. I did a Chat search for more info on the centering sleeves and it says that when you insert the sleeve you knock it in until it bottoms so presumably the “a” measurement results from the sleeve being made the appropriate length. It’s not actually inserted to a specific depth. I’m leaning toward changing the sleeves I think because I have it all apart and I just want to do as thorough a job as possible. Of note the change in the “a” measurement appears to be only for the rear sleeve and the listed value in the manual is currently consistent with the depth of the rear sleeve on my car. The discrepancy on my car is between the front sleeve which measures 24mm on my car but the manual says 36.3mm.
Mike
Last edited by mike10E350; Apr 30, 2026 at 11:27 PM.
Dont worry too much on the "height" which you call depth , of the alignment sleeve.
As long as the penetration of the male protrusion of the tranny side is long enough to maintain alignment ( with flex disc sandwitched in between ) of say 15mm insertion, it is good enough. 15mm is 0.59 inch.
Also get a better flat edge, dont use that distorted square ALU pipe. Get a JIC Class 1 measuring tape too or a caliper.
You also seems to not know inch to millimeters conversion
I am seeing the measurement is tilted, not only the inch to millimeters conversion is wrong.
ABOVE : Why you said it is 24mm when it is at least 28.58mm ?
======================
BELOW : My eye ball is seeing 31.75mm, when and if you use proper flat edge and tape or a caliper.
The tape is cheap, for JIS class 1.Get TAJIMA brand. Its popular in USA too. Get millimeters version.
The dumb azz inches measuring tape increment is so bad at 1/8" which is 3.2mm, how can you use it for accuracy work demanding 1mm ?
The habit of reading/printing in fraction 1/8" ( 0.125 inch ) is wasting valuable space on an already small tape .
The millimeters line or increment is worth 0.039 inch, which I do not know the fraction value ...LOL , but it is 320% more accurate an increment over the inch measuring tape.
-------------------
The front end ( tranny side ) of the propeller shaft would be similar to the rear end or DIFF side. Mine, DIFF side only.
.
Stay safe under the car............
Last edited by S-Prihadi; May 1, 2026 at 04:34 AM.
Reason: add info
Yes I hear you on your points and I can use my straight edge and caliper but I don’t think it changes the measurements. I’m measuring from the highest point on the driveshaft “yoke” you seem to be measuring from the base of the yoke? See attached pics. The measurement your speaking of I already calculated as 28mm but that’s the rear one which is actually on target with the manual. The front one I measured at 24mm which is much less than the manual 36mm. Even if I measure from where you do it’s still almost a cm off. I’ll take new measurements with my straight edge and calipers but it’s still not gonna be close to 36mm. Thoughts?
As I said : As long as the penetration of the male protrusion of the tranny side is long enough to maintain alignment ( with flex disc sandwitched in between ) of say 15mm insertion, it is good enough. 15mm is 0.59 inch.
The true alignment in the end are the bolts of the flex disc and how good is the new flex disc shape.
or
You buy new sleeve and make the measurement like what WIS stated, but do becareful if the sleeve too long, it may touch or hit the male protrusion of the tranny side too early, aka sleeve too long.
Do a proper simulated measurement, it is easy.
So I’m installing the new flex discs and the torque specs say 68 NM but what I’ve noticed is the replacement lock nuts provided with the flex discs have such restriction when tightening that the torque is achieved and the bolt is still able to be turned with the wrench pretty easily. The nut and bolt turn as a unit of course, it’s not so loose that the nut spins or anything, and I definitely cant turn it with my fingers, but with a wrench on the nut or bolt I can rotate them both easier than I would have expected to. Is this ok?
Yes bolts are the same length as the originals and I did have to put a wrench on them to remove them. Washers are installed. They are clearly “lock” nut style nuts so they aren’t supposed to spin easily. Im just I guess a little surprised how hard they are to turn. I’m thinking that I may bump up the torque a little to maybe 75-80 NM. I don’t think that will significantly alter the flex disc performance and it will ensure the nuts are sufficiently tightened.
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
.
