nota_amg

So...I finally got around to changing my front driveshaft with the aftermarket one I bought a couple months ago. I noticed a slight vibration a while ago and saw the u-joint was dry and had play in it when I installed my downpipes. I tore everything down and installed the new shaft with no issues. Drove out of the shop, attempted to launch the car and it felt "spongy". I tried again, foot on brake, load to 2,200rpm and BAM!!! Twisted the brand new driveshaft IN HALF! I mean, like it was made out of paper. So disappointed in myself, I should have known better. Anyway, I have a used factory shaft coming in on Wednesday and I'll be installing it Thursday morning. I'll post pics of the carnage then.

belarus27

When i had vibrations i took the car to the shop and they found my flex discs were loose so they tightened them and the vibration went away.

Sorry about what happened. I hope it didnt damage anything.

95Sinned420

U Joints.. did you mean the flex discs?
Why did you have to replace the drive shaft in the first place? Not because it had bad flex discs right?

nota_amg

no, FRONT driveshaft...no flex disks on it. Female spline on trans side, u-joint on differential side.

VegasE

Similar happened on a friend's Audi TT. Installed aftermarket shafts made in China. Lasted about 200 miles before disintegrating on a vacation.

95Sinned420

I see, for the 4matic. Makes sense.

nota_amg

you got it!

ugh...one more day...It feels really weird not having my car. Come on Thursday!

S-Prihadi

Dang, power of proper mettalurgy vs unknown.
It reminded me of a friend's yacht. His 45 footer with 550HP detroit diesel went aground.
To speed up things, he went for 316 SS shaft instead of original propeller shaft which is usually special branded alloy called Aquamet 22 which needed to be imported and will take 2 months.
In under 50 hours of use, the 316 SS twisted and became useless.

Why did u change drive shaft to aftermarket one in the 1st place ?

mskembo

I'm going to go out on a limb and say it was financial considerations.

nota_amg

yes, it was almost $800 for a new one from MB vs $100 for one from ebay. I knew it was a gamble. I bought it months ago when I first discovered the issue with the bad u-joint(I have a quick video of the u-joint slop I'll post here tomorrow as well) and it's been sitting in my garage. Not to many launches on it after I discovered it and realized the noise and vibration from it were getting worse, but it still held up. I could have reinstalled the old one and drove the car, but decided to just leave it down till tomorrow and fix it then. Don't want to do the job 2 more times...once more is enough. I found a used shaft for $300 with very low mileage that I will be inspecting thoroughly before installing it, and it has a 6 month warranty as well...just in case, lol.

mskembo

I get it! I've made similar gambles multiple times. Hopefully it didn't tear anything up when it turned into a pretzel.

nota_amg

O2 sensors and wires looked good and no CEL. Fingers crossed

nota_amg

Here is the old joint/shaft:

Here is the cheap-*** POS shaft after attempting to launch the car:

pierrejoliat

Yes, I have built a number of alcohol plants, we always look at the price of Chinese tubing and piping, but the metallurgy is always deficient, we buy all our Stainless in the US, just not worth the trouble of inspecting every pipe in the bundle, or having pressure blow-outs, pitting and rusty stainless!