Causes for flex disk to wear/break prematurely?

[lagoon]

the flex disk on my car recently split. i spoke to the PO and he said it was replaced about 6 months ago. i have the receits for the flex disk that the PO bought and i trust he did replace it.

anyways, since the flex disk was replaced 6 months ago, what would cause it to break so soon? i've read that the driveshaft may be out of balance?

does anyone have any input on what the problem could be? i'm going to replace the flex disk, but i was wondering if i should just replace it and it call it a day, or further investigate why it broke. the disk itself could have been faulty, or the installation might not have been done correctly, but if there are any other causes, i would like to look into them and make sure everything is taken care of.

TIA

[lagoon]

PS. car is a '91 318is.

here is a quick illustration of where it cracked/split:



the red indicates the crack/split..

[browntown]

these are pure guesses:

a.) driveshaft not balanced
b.) guibo bolts not properly torqued to spec

[lagoon]

a.) driveshaft not balanced

yeah, that's what i was thinking. how can i check if it's not in balance?

[browntown]

without a shop doing it? no idea.

[lagoon]

shop it is..

thanks.

[mspiegle]

improperly installed. I did a replacement once, didn't install it right, and it went out in 3-4 months (Really hard driving). I replaced it the right way and its been going fine for quite a while now.

[DanielHStout]

What is the right way and what is the wrong way?

[Sean]

Bad engine mounts and tranny mounts would be a lot of load on the flex disc too. But, I'm sure you'd see that.

[cactusjacks1]

Is your disc OEM? Have had the same problem with 2 aftermarket ones in 6 months. Drive shaft is new along with center bearing & trans mounts. In the process of ordering a OEM one now. Any other reasons you can think of?

[1990m3]

how do you install a flex disc improperly. I've done it 3 or 4 times, AFAIK there is only one way to install them otherwise it just doesn't work at all...

[Sean]

how do you install a flex disc improperly. I've done it 3 or 4 times, AFAIK there is only one way to install them otherwise it just doesn't work at all...

Indeed - as described in the bentley. Arrows point to the part it bolts to.

[arsevader]

Indeed - as described in the bentley. Arrows point to the part it bolts to.

Also known as the flange... ;)

[Sean]

Also known as the flange... ;)

HAHAHAA...

thanks. :drink:

[lagoon]

how do you install a flex disc improperly. I've done it 3 or 4 times, AFAIK there is only one way to install them otherwise it just doesn't work at all...

i think in some cases it may not have been torqued to spec.. correct me if i'm wrong.