RE: Cracked Necks?????
Annealing properly is difficult. Most procedures like from John Barsness only stress relieves. He tells people to just heat the necks until you fingers get hot holding the brass. I totally disagree. You need to buy a temp sensitive crayon (welders use) and a propane torch.
Annealing can help with your problem, but should have never happened in the first place if they annealed correctly.