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E320 flex disc, propshaft centre bearing, transmission mount

10K views 6 replies 5 participants last post by  Jason535 
#1 ·
Hi there.

Hope everyone is enjoying their awesome E's. :)
I need some advice on the above mentioned parts. I decided yesterday, after losing my marbles after only 3 hours of sleep, that my propshaft is coming out 'like right now'. It happens :rolleyes:

THE REASON for parts replacement : Vibration at 115 km/h getting worse from there and never stops upwards. I've been replacing other possible 'vibration causing parts' and so its time for this now.

Anyway, few hours later parts were out, I emerged looking like a coal miner.
I bought a non Mercedes brand flex disc awhile ago. Been wanting to put it in, but it looks very different to the original.

So here's my questions. If anyone can provide any advice it would be much appreciated.
1. The flex disc I bought is bigger in diameter, and much heavier then the original. Also it has some kind of metal clips (non removable) Do you think it is ok to use it? Will the size and weight difference perhaps affect the shaft balancing? (see photo's) (old = 600g new = 1.1kg :eek: the holes are the same atleast)

2. The Center bearing still rotates fine, no noises, and the rubber is still without cracks. Should i replace it?

3. The transmission mount : how stiff must the rubber be? I Can move mine by applying pressure with only my thumb. (movement of about +/- 2mm no cracks though)

4. There is some sort of damage to the transmission shaft surrounding area ( see photos) not to the shaft itself atleast. Is this something to worry about?

Thanks in advance.
Apologies for the poor quality photos, better ones can be obtained if need be.
:thumbsup:
 

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#3 ·
I would go with an OEM flex disc and new transmission mount. If the seal on the center bearing is ok the bearing should be good. I would not mess with it. On each end of the propeller shaft where the flex discs attach is a bearing -- check and see if they are ok and if so lightly lube when you put it back together and you should be in good shape.
 
#4 ·
you have to be very careful how you install either type, the originals have a thicker section between 2 of the holes and then a thinner section then a thicker section between 2 of the holes etc.
depending on the direction of rotation of the shaft (in a forward gear) you have to put one leg of the yoke of the shaft and one leg of the yoke on the dif into each hole so the thickened part is under compression when driving.
same thing for the clip type - the thickened edge of each hole has to be on the side opposite the compression (so you are pushing against it).
If you dont they will start to fail within a few thousand miles.
attached is a picture of a landrover one, they mark theirs to make it easier but I have circled the thickened area.
with my untraceable vibration I replaced everything but mine was due to the rear transmission mount. If the center mount is good leave it alone!
keep well
Barri
 

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#5 ·
Are you using O.E.M parts? Not sure for the difference in sizes if it is an OEM part sprcifically for your year and model? Did you have to provide your VIN number when they ordered your part? Keep in mind that rear wheel bearings or carrier bearings in the differential are FAR more likely to fail and cause the noises you described. Flex dics and center support bearings typically will last the life of the car unless damged by a major under car hit. Good luck and please let us know how it turns out.

Regards
 
#6 ·
Thank you everyone for their replies.
@ gurunutkins - I will take special care when installing them, thx.

I always use o.e.m products, they take my vin etc, no problems with that.
This is the first time I've tried non Merc, I jst couldn't afford R1200 (+- $160) for the o.e.m one. But I'l bite it and go purchase the o.e.m today :) Same for the transmission mount, Merc brand shouldn't be too expensive for that though. . . I hope not.

Will be doing the re-install today. I'll come post back when I'm done and if it improved the vibration. (eliminated I mean)

If it still vibrates next step would be front rim straightening. Have been told over and over they're fine but going to do it for peace of mind. (they fix the scratches too, so it ends up looking new ; a bonus :thumbsup:)
 
#7 ·
So I managed to install the parts yesterday, and today went to church (they have lifts there) to make sure everything is tight and happy.

I decided to use one non Merc brand flex disc and one o.e.m flex disc. Also bought the transmission mount. Didn't touch the center bearing, except with some lube, and the shaft end with some grease.

A couple of pointers for other people who want to do this replacement as well.
- A brand new transmission mount is supposed to flex +- 2mm, i found no difference with the new and old. Waste of money:(, I consider it money spent on training/learning at least.

- The non Merc brand flex disc : Ditch the bolts (at least on mine) They're too short, don't go through the whole nut. When I tried to fasten them in final tightening they stripped. Couldn't get the nut off the damn stripped bolt. Insert screw driver in the side, hit with hammer. (all sides of the nut) and off she falls. :surrender:

- Not sure how other people did it but - the heat shield didn't want to totally come out so I left it laying on the exhaust. Struggled my butt off to remove the propeller shaft because the center bearing mount hooks. Solution : let the gearbox and exhaust 'hang'. It won't fall down. Then just wiggle. :)

- Finally : Before attempting anything! Have a beer. then during operation another.

I tested the final result by putting my foot down, full throttle, 1, 2 and 3 gear. Very smooth. Couldn't attempt high speed though, but if my theory is correct a smooth propshaft at 0 - 100 kph indicates its not the cause of my high speed vibration. Next up - Refurb and straighten front wheels. Get a Merc tech to fix my damned allignment! Thats a story on its own. Will post it up in the future.

Peace :thumbsup:
 
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