Another Hoffman differential loop, few rads don’t heat well

GW

@Steamhead and @Gordo I tried turning the old 17, just a bit. It seems to 'close' (a bit), but then it would not go back to where it came from. I watched your vid on the 17 repair, seems doable. Can I buy the special parts anywhere? Can I send yopu some dough and maybe get some parts? Whats that tiny tool/jog you had (that allowed for the wrench)? And the gasket material, do i need to buy a gasket making kit? Thanks