300E Flex Disk Replacements
 

I am trying to narrow down sources of vibrations in my 1986 300e. I know for certain that the differential mounts are toast. I will have to get the car into the indy to take care of those, but I noticed that the rear flex disk has a crack leading from one of the bolts to the exterior of the disk. I assume that means it is time for a new one, and I like to do packages of things, so I would like to do the front and the bearing at the same time.

Questions:

• Are there any special tricks to replacing the flex disks?
  
• Should the center bearing be replaced at the same time?
  
• Does the bearing just slide off the end of the shaft?
  
• Can a guy do this by himself without a lift?
  
• Can two guys do this without a lift?
  
• Will the shop doing the rear diff mounts be in a good position to replace any of these parts?

Thanks for all your help! And thanks for helping me make a good W124.

I'm sorry to ask a question that I am certain has come up before, but I wasn't finding a straight set of answers using the search.

For sure you can do it yourself with a few basic tools and some decent ramps.
2 guys will be even better.
The most important tool is patience, the flex disc bolts are self locking so you're best of putting them on once, but if you do have to undo them and redo them again, use thread lock, they also strip easily with threadlock, so be careful.

Before you dissassemble everything, spend some time looking over the driveshaft, it looks simple, but there are some marks on it that will need to line up if you want a smooth ride. The front dlex disc is much harder access wise, and with the rear flex disc on, the front one will not clear the transmission.

Not too sure about diff mounts, but I imagine with the shaft off, it would be real easy to do.

The bearing will come out on its own, but you might as well get the center support since if you try to pull out the old bearing from the support, it will most likely fall apart, so save yourself a headache, get the support as well as the bearing and do it all up in one shot.

So, key points, inspect everything closely, take off the support bearing, take off the rear flex disc, then the front, then do the diff mounts, and install everything in reverse order paying attention to the marks on the driveshaft.

It'll be like a new car after you do this right, count on it.

xp

Is that to say that I don't need to worry about the relative position of the disks themselves? (Assuming that they are facing front to back correctly)

The flex discs are marked as to which way they are supposed to face relative to the car, but other then that they go any which way.

xp

writing on flex-disc
 

Yes, isnt it usually "zu getriebe" (or something like that in German), which means this side to face the gearbox.

I have no idea if it's necessary but I have always replaced them in exactly the same position, down to the position of the writing. Once you get a red magic marker down there and start marking things it's not that hard to do.

Two more questions:

Does anything pass through the center of the disks, or does all of the car's power go through the disk itself?

Do I need to worry about disconnecting anything on the driveshaft beyond the six bolts per disk?

Thanks for your help!

All the power is transferred through the disks. And the six bolts per disk is all there is until you do the support and bearing. And two guys would be good, I think you would be able to do the diff mounts yourself and save the shop fees, They're not all that difficult. a couple of ramps, or a floor jack and some jack stands. Good luck and have fun!!

What is involved with those?

I'm just trying to make sure the two guys in question are armed in advance. :cool:

A hammer to tap the old one off, unless you have a press and a piece of pipe to install the new bearing, and i believe the 2bolts take a 15 mm socket.