I was under the impression that this job was straight forward.....and it is straight forward reletively speaking, but I cannot get to several nuts and bolts at the top and front of the disc. My disc is pretty much shot and I ordered a new one (unfortunately I ordered the rear instead of the front, but I believe the only difference is the bolt legnth so I'll reuse the ones I have.) Does the flex disc rotate around so I can have easy access to it? Someone please help. I have 2 of the 6 bolts out already.

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1990 190E 3.0L

The disk can be rotated by jacking up the rear wheel and A/T in N. this will give you the required access. Also note the orientation . The face marked "deis sitte d " faces the drive shaft .
regards

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mark

Do yourself a favor and put a jack under the transmission, unbolt the (13mm?) bolts that hold the crossmember in place. It makes the flex disk swap 100x easier. Trust me. You will have issues torquing up the flex bolts with the new one in place. It'll be a big PIA.

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2016 Monsoon Gray Audi Allroad - 21k
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2003 Gray Mercedes ML350 - 122k

To all of you that chimed in to help, thank you very much. I was able to do the swap by letting the rear tires rest on the jack stand and manually turn the drive shaft. As I mentioned before I ordered the wrong flex disc (I bought the rear instead of the front), but the only difference I noticed were the bolts, so I just used the ones I had. Does anyone seee a problem with this or am I good to go? I have pictures of my worn flex disc, check it out.

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1990 190E 3.0L

There might be an issue with using the rear flex disc on the front. They are sold with two separate part numbers. So there must be a difference. They do appear slightly different, but I don't know what issues would be caused by using the rear disc for the front.

Surprisingly the flex disc you removed is in good shape compared with how they typically look.

Here is a picture of the front vs rear. You can see the front has off-center eccentric looking mounting holes while the rear does not.

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http://i193.photobucket.com/albums/z...-RESIZED-1.jpg
1991 300E - 212K and rising fast...

Yes, I do see the difference.....hmmmm, But the thickness seemed the same and I did not noticed the holes until you showed me this picture as mine was so mangled and every single bolt was actually just wobbling in the hole as the metal center fitment broke loose from the rubber, which explained the constant clanking noise I heard. Anyone, know of any adverse reactions to using the rear disc in the front? BTW, car seems to drive alot quieter and smoother

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1990 190E 3.0L

I don't really know of any problem offhand...but...I'd have to assume that if the duty of these parts were interchangeable I couldn't imagine MB spending tens of thousands of dollars to a company for tooling up to pointlessly manufacture another part just to look different than its counterpart.
Personally. I wouldn't be real comfortable switching them. No offence, but you're kind of whitewashing one mistake with another mistake. Save the rear disk for when your rear one goes, it probably won't be long if one failed already, and get the right one for the front.

I also noticed that the hardware for the front is quite different. The shoulder length of the bolts is short for half the bolts, long for the other half. The design difference and hardware difference is probably because the front disc takes a lot more torque, power, abuse than the rear disc.

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http://i193.photobucket.com/albums/z...-RESIZED-1.jpg
1991 300E - 212K and rising fast...

Looking at the pictures above, it seems like the front one, with those elliptical washers and reinforcing berm of material on the one side of them maybe gets more stress or compression, perhaps from the direct torque of the transmission, than the rear one does.


Obviously just naive conjecture, but there's must be some good reason for the differences. The front one is more expensive than the rear as well so there may also be structural or other differences that are not apparent or visible.

Yeah, I just got home from a brief test drive and my car feels better than ever. I'm currently looking at my old flex disc and I see that the structural difference my be mecause of the shifting of the gears from drive to revers, etc....and that the front probably does endure more stress. Now, I'm kind of at a toss up because the rubber is what holds the beams in place, and the thickness on both were equivalent....I'm wondering that since these parts obviously last about 250k + mi. anyways if it would be worth it to replace it out. My car is currently at 275k mi, een if the extra stress did wear the disc out and cut the time of wear in half that would still give me 125k mi......I can see any of you frowning at me for thinking this way. I'm somewhat confident that MB spent that $8 million in research for this car to ensure that the endurance of the parts were superior (its just too bad that they decided to use a bunch of plastic under the hood and in the body work :0)

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1990 190E 3.0L

I would not do that, the driveshaft is balanced from the factory and even a minor change like that could be bad. I can't tell you what may happen, but I personally wouldn't advise you leave it be.

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k

"A soft flexible coupling is used on the transmission side to cushion acceleration and deceleration shock loads and a standard flexible coupling is used on the rear axle."

This is from the book for the Model 201.

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63 190d (sold)
69 220D (sold)
69 280SL (sold)
76 BMW 2002 (sold)
86 190E-16v (Demised at Laguna Seca Turn 9)
87 300SDL (sold)
87 300SDL 135k
87 300TD 280k (sold)
95 E320W 211k
95 E320w 111k
05 C320 4matic
06 E320 CDI 90k (Totaled by a texting 19 year old girl in a nissan)
2013 GLK 250 Bluetek 4MATIC

I figured it wouldn't be any different then how some people end up swapping out parts.....say 500E brakes on a 190E or adding totally different parts instead what was put on and tested at the factory. But, once again I'm not opposed to reason or common sense so I will order the proper part and get back under there and swap it out. Thank you all for your input and time on this matter for helping me figure this out.

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1990 190E 3.0L

Yes, but a balanced driveshaft is a completely different story...

Just remember, you are used to a cracked and worn driveshaft, so even an incorrect part is going to feel like a world of difference, even though it is wrong. The correct thing to do would be to ensure you have the correct part for balancing reasons as I stated. *If* you do plan to leave it as it is, don't expect it to last long (30-60k miles tops) and also keep in mind you may cause inadvertent excessive wear on other items such as the center support bearing and rear flex disk. I personally wouldn't feel comfortable.

I think it would definitely be a wise decision to put the correct one on.

Also, I don't know what mileage you bought the car at, but I am 90% sure that is not the original disk. My experience has been they are pretty much toast at 100k miles (2 W124's and 1 190 2.6 doing this job)....275k on the original would be very surprising!!

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k

I've seen an original with 150K, and the fabric core of the damned thing was unraveling in long strands, all of the bolt holes were ripped loose. It made a little bit of noise, yes.

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http://i193.photobucket.com/albums/z...-RESIZED-1.jpg
1991 300E - 212K and rising fast...