I noticed in my manual at 41.1-200/4, number 5 says, "On vehicles with tangentially soft flexible couplings (soft push-pull) loosen the vulcanized fitted sleeves out of three-legged flange. For this purpose, use a cylindrical mandrel of 10 mm dia. and approx. 150 mm in length."

I wonder how you can tell whether your vehicle has a "tangentially soft flexible coupling."

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1993 400E, 256,000 miles (totaled)
1994 E420, 200,000+ miles
1995 E420, 201,000 miles

It Apparently has SIX Flat sides.(?)

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'84 300SD sold
124.128

Looks to me like they are trying to loosen the metal spaces in the flex disc from the vibration damper(?). They are probably a tight fit ... Putting something in to wiggle them out instead of prying on a flange your going to be reusing.


Michael

So, I got my hands on a new flex disc and thought I would crawl under there to see if I could swap out the front disc. I jacked the front of the car up and supported it with jack stands. Then, supporting the transmission with a jack, I took off the transmission cross member to gain better access to the flex disc.

That's when I realized two problems I was going to experience:

(1) there is no way to get to the top bolts of the flex disc without rotating the rear tires to turn the drive shaft and the tires were firmly on the garage floor (my one jack being used to hold up the transmission and one set of jack stands holding up the front of the car);

(2) getting to the big drive shaft clamping nut in order to slide the drive shaft back would involve removing a section of the exhaust, which I noticed had a hairline crack on one of the flanges and would definitely need to be replaced.

I gave up on the front and thought I would see if I could at least replace the rear disc. It would be easy enough getting to the rear flex disc bolts once the rear end was jacked up and supported, but there appears to be some sort of centering bushing either going into the drive shaft or into the differential flange that would prevent me from slipping the old flex disc out.

The flex disc went back into the box to be saved for another day. This was much more involved that I had hoped.

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1993 400E, 256,000 miles (totaled)
1994 E420, 200,000+ miles
1995 E420, 201,000 miles

I'm a little hazy on this but I think I put the two front tires up on 6 inch wood blocks, held up the transmission with a screw type jack stand (Walmart RV levelers are great) and then raised the driver side rear wheel and inch off the ground with the good jack. You only have to get the driver side wheel off the ground to turn the driveshaft. Remove the flex disk bolts, telescope the driveshaft as much as possible, pull down on the driveshaft as much as possible and pull the flex disk out at a 45 degree angle. It seems like you may have to loosen an exhaust cover or something to get the driveshaft pulled down - can't remember, but not a big deal. It's one of those things that you can do the second time in an hour. With E-brake off and transmission in neutral you need some good wheel chocks too.

Thanks, Deanyel. I'll probably give it another try when it's not 106 degrees out here in Tucson (112 for you). With regard to the rear disc (the bolts seem much more accessible), if I took the exhaust shield off and removed the bolts from the rear flex disc, do you think I would be able to pull down on the drive shaft and get the rear flex disc around that centering sleeve between the drive shaft and differential flange? It looks like a small space. I'm not sure if your post above was related only to the front flex disc.

Good point about the parking brake.

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1993 400E, 256,000 miles (totaled)
1994 E420, 200,000+ miles
1995 E420, 201,000 miles

Does anyone know if it is even necessary to loosen the drive shaft clamping nut in order to get enough space to slip the front flex disc out past the centering bushing?

I read somewhere that loosening the clamping nut is unnecessary because you could get enough space by pulling down on the drive shaft; but looking at the diagram, I'm not sure if this also requires removing the mount bolts for the intermediate bearing.

If I remove only the heat shield above the middle muffler, I don't think I will be able to get a wrench on the clamping nut without taking off the entire exhaust from the cat back because the rear of the car is not raised and I'm concerned that just allowing the rear muffler to drop to the ground won't create enough room to get in there with a big wrench.

Any help would be appreciated. Without taking the heat shield off, I don't have a very good picture in my mind of how things are situated up there.

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1993 400E, 256,000 miles (totaled)
1994 E420, 200,000+ miles
1995 E420, 201,000 miles