I rebuilt my hayward pump with new bearings and shaft seal and when I went to clolse up the shell or pump housing the O-ring that sits in this grove between two halves is too long to fit in groove. its sat night and i want to finish something i start for once so does anyone know how to shrink the O-ring temporarily to get pump halves together.

Saw many conflicting answers on the web but mostly related to auto part o rings.