I just finished rebuilding my torque tube this weekend. Put in new NTN C4 bearings in the stock Carriers which were in good shape. The inner bearing sleeves however I replaced with polymer units I ordered from:
https:/garage9.com/collections/944/products/copy-of-bearing-sleeves-25mm-or-28mm?variant=13068228001844
I however noticed the driveshaft was alot easier to reinsert in the tube with the polymer sleeves than it was taking it out when it was the factory rubber sleeves. I was able to push it in by hand (with some resistance) without any need of mechanical aid contrary to when I took it out which required alot of banging. To whoever has rebuilt torque tubes, is this common with these polymer sleeves because the material has less friction resistance or should I be worried the shaft will at one point start spinning in the sleeves and end up destroying the?. According to the website they are supposed to be CNC machined to precise spec.

 

I have rebuilt my torque tube twice (on the same car after my NTN C4's started making noise) and both times I have reused stock rubber sleeves. Taking the driveshaft out required tools, but when lubed up, I managed to push the driveshaft back by hand as well. After it got throught 4th bearing I barely had the strength to push it to its final place. In fact I tried to have local machine shop make polymer sleeves, but they ended way too loose. If you can move the drive shaft back and forth through all 4 bearing sleeves without much resistace It's too loose.
If I had to do it all over again, this time, I'd just get "super bearings" from Black Sea.

 

Yea those garage 9 inserts are junk, i have mine made locally. and honestly when i sell them as set to customers i size them up exact, the painted shafts and non painted will sit different there is a slight tolerance difference.
a customer bought those and brought them to me... they had like a gap arround the shaft, the companies response was use silicone to hold them on... what a joke
i make a batch of like 200 at a time, and than when people need i confirm painted or bare steel shaft size them exact than clean and send out.

even with new inserts it should take some force to install the carriers back if they slide in by hand... they will likely move...

 

Tim, would you be willing to sell me some? A friend and I are rebuilding our torque tubes at the moment and already damaged at least 1 stock insert so far.

 

Baffles me how a company can sell a product they haven't even tested. And if they did and haven't realized anything its even worse. Anyways looks like i'm ****ed, not gonna take out all the carriers to replace sleeves way too much work, maybe gonna try coating the shaft with epoxy paint to give it a little extra diameter.

 

We have rebuilt our share of "rebuilt" TTs.

Delrin or other hard plastic type inserts, not to mention aluminum which some have used, will wear rapidly with use. The drive shaft will then resonate within the bearings and cause NVH issues along with clutch engagement issues.

This extra resonance will also damage the drive shafts and splined ends of the drive shaft.

Sorry for the bad news.

Edit:

Will add that re-using the old inserts has the same issues. Sometimes the act of dismantling the bearing unit damages the old insert. They can also be damaged when reinserting the drive shaft back into the TT. The old inserts should be looked as a one time use item.