Anyone here have experience with disassembling Faber Castell ballpoints?

I managed to pick up an “alphamatic bronce” ballpoint for a below-market price, because the seller said it had a fault–the tip won’t stay extended. A little pressure and “pop,” the tip retracts. Since I’ve been fairly successful with DIY into “zones unknown,” I figured this might be worthwhile. After all, the body looks only modestly used, with just minor scratches. It presents nicely.

Well… it’s more of a mystery than I anticipated. I did discover that the clicker cap has a friction fit attachment to the plastic core. With some firm, gradual pulling, I was able to detach it. Everything still intact, nothing broken. But from there? I can’t see how the mechanism is released. I applied a little forward pressure with the cap off, but it didn’t budge… so I backed off. I tried twisting the mechanism core plastic post and it turns… but it just rotates in place. There’s no unscrewing happening. So… I’m at a bit of a loss as to what to do. I certainly don’t want to experiment much more, for fear of breaking the mechanism. Also, when unscrewing the front piece and detaching the cap, no plastic pieces fell out. So it seems it’s intact. I just don’t have any clue as to why it’s malfunctioning.

There must be some special technique to extracting the mechanism and it probably requires a proprietary tool. When you look into the barrel while pressing and releasing the cap, you don’t see anything move. When you put in the refill and then push down, there is some travel. So the refill must sit inside with the spring providing pressure and then the cap pressed activates a rotation inside. There is a very small hole in the center… and what I’m thinking is that there is some device that you insert and then pull to extract. But again… a mystery.

FYI: As for usable parts, I sadly discovered that the cap has a very short shaft to it–totally incompatible for a swap with the alphamatic pencil cap. The front section is also incompatible as the tip diameter is wider on the ballpoint.