Replaced front flex disk in 240D - PeachParts Mercedes-Benz Forum

Rmcfarland · #1 06-30-2007, 05:30 PM

I know this has been covered before, but, I replaced my front flex disk and center driveshaft support. I didnt change out the bearing (I know, bad) but I don't have a bearing puller. I did all of it without unbolting the rear flex disk.

Here is a picture of my bad flex disk in the front. I think I am lucky it didn't break apart while on the highway. Good thing the ol' 240 doesn't have more power, would have ripped that sucker apart!

Thanks to all the people on this forum, I would have not attempted this without the help posted here. Also, everyone should check their disks if you haven't already, not only could it save your car's life (or yours), it drives smoother too!

Here is what I did, anyone with a few hand tools can replace these.

MARK ALL CONNECTIONS ON THE DRIVESHAFT with whiteout or paint. Make SURE and get it back the way it was so it will be balanced!

I put the rear of the car on jackstands and chocked the front wheels.

I then unbolted the 6 bolts on the front flexdisk.

Then I took the two bolts off of the center mount.

Next, I loosened the large collar nut in the center of the driveshaft. This allows the shaft to shorten and will make your life easier. You will also curse significantly less. Some PB blaster will go along way here.

Collapsing the driveshaft make flex disk removal easy. A prybar and hammer helped seperate it.

Push the front half of the driveshaft forward, so the two halves come apart in the middle. The driveshaft can just sit there kind of on top of the transmission.

Now, the fun part: I used a hammer and a screwdriver to pound the old center support off of the bearing. Hitting it in a circular motion with the hammer, glancing blows all around the ring freed it up. I found it to be much easier to tear what little of the rubber was left off, so the outside of the mount was not in the way. Once again, PB is your friend. Sliding the two halves of the driveshaft back together helped me hold things steady as well.

Now you should be able to slide the old center support off the end of the driveshaft. put the new one on the bearing and use the hammer to pound it back on the bearing. Don't hit it too hard, otherwise you may destroy the bearing. It didn't take that much force for me to get it on there.

Place the new flex disk on the transmission end. Bolt it to the 3 holes there before you put the driveshaft back on it. This just helps hold everything in place.

Put the bolts back in the driveshaft to flex disk. Make sure your paint marks are all lined up. The driveshaft will extend to the length it needs to be as long as that big collar nut is still loose.

Now, tighten up all the flex disk bolts real gewd. If you have a torque wrench, good luck figuring out how much that is.

Put the two bolts that fix the center support to the chassis back in.

Tighten that collar nut on the driveshaft. You should be done now, lower the car and enjoy your smooth, clunk-free and less deadly driveshaft.

Total time: 3 (Fairly leisurely) hours.
Tools I Used:

15mm socket+extension for flex disk bolts
13mm socket for driveshaft support bolts
Big Ol' Adjustable Wrench+my foot for loosening collar nut on driveshaft
Hammer for Beating On Stuff (flex disk and center support holding bearing)
Pry bar to free flex disk
Screwdriver to use as a chisel (to remove bearing support again)
PB Blaster spray (kinda like WD-40 on steroids) to loosen everything up
Smaller adjustable wrench to hold nuts when turning flex disk bolts

I think that's it. Hope I didn't forget anything, but my point is anyone can do this if you have a few hours. You don't need anything real fancy, I just did it in my driveway.

Bama1 · #2 07-01-2007, 01:50 PM

Good job, well done! ...and a big reminder for all of us to have a look at our own.

Picture says you timed this repair just right. Now you won't be stuck on the side of the road with a shaft stuck through the floorboard!

Make sure to check all the bolts after a few hundred miles and again after a few thousand...just to be sure.

Rmcfarland · #3 07-01-2007, 05:38 PM

Thanks for the advice... will check bolts again soon. Not too bad of a job, really. I have a lot more peace of mind driving the car, too.

dwoloz · #4 07-01-2007, 06:05 PM

How did you discover the flex disk was bad?

RML · #5 07-01-2007, 08:00 PM

Thanks so much for this very informative and detailed post. I need to do this on my 84 300D. I was not sure how long it was going to take or how difficult it would be.

Richard