I just received a burgundy Osmiroid 75 from Ebay but the pen has a problem. It seems that it was disassembled for cleaning prior to sale and now the whole pen comes apart easily. The see through window between the barrel and the section is off set so the cap doesn't sit right and it won't screw on (might have been forced but the threads don't look damaged). The piston itself just lifts out, even the end of the barrel detaches easily.
I've renovated several Esterbrooks so I'm not worried about the disassembling bit it's the fact nothing stays together securely now. Obviously as it is I can't put ink into it and the seller has refunded the purchase price but if there's a way of fixing it I'd love to have a go as it's a very handsome pen and apart from the whole falling apartness of it, the pen seems to be in very good nick.