I can't get the belly ring back on my filter - took it apart to clean. Pac Fab Nautilaus 60, or same as Pentair??, stainless steel model. There's a rubber gasket and a metal clamp that needs to clamp around the middle closing the top to the bottom. The top wont set all the way down over the gasket and the metal ring is about an inch off from closing. Tried and tried to pull it together but it just won't close. Any tricks to pull it together to seal?