On Sunday, March 8, 2020 at 4:23:09 PM UTC-4, wrote:
I wrote couple of email's to LTB Lindner but they did not respond at all. That id not tipical German behaviour. From mine personal experience Schempp Hirth and Alexander Schleicher are much more serious snd quite responsive.. Regrds Joško

Josko,
I asked Linder the same thing about the manual and would not sell it to me. What I found out, that they have a blue print (original drawing) that they would sell one small part at the time. I ordered bolts and locking nuts from them. The nuts were not matching the bolts. They made me send them back and I did. Linder never sent me the replacement parts. As the manual I have a very tiny part of the original drawing for those small bolts. I can only way check out on a correct assembly that I travel 2-3 hours to see an other Grob 102 and take lots of pictures. Good luck.