Got a project bike a few weeks ago that needed to be greased throughout before use. It's a mid 80's Fuji Sand Blaster youth MTB. Appears to have a 68mm BB tube .

After cleaning/lubing the BB, the bike doesn't want to hold a BB adjustment, loosens quickly in use. After the second failure, I disassembled it, cleaned the threads with alcohol, applied blue Loctite and let dry overnight.....no luck as it went loose very quickly. threads in the frame, cup and lock ring seem good (albeit somewhat easy to turn). Try again with red Loctite? Just replace it with a cartridge, but won't those threads loosen, too?

Suggestions appreciated, thanks for your time!