Start by cutting the top ring with a very sharp knife,
place a screwdriver in the cut and carefuly pry the top ring off. To replace, i sprayed the diahpram with some silicon spray and carefully put the upper ring back on, the lower ring has a recess and the bottom of the diaphram must sit in this recess to seal properly, carefully pull on the diaphram till you feel the diaphram seat in the lower ring recess.
Because the diaphram is a pressed fit youll need to tap the upper ring lightly for a secure fit
i used the handle of a screwdriver, being careful not to damage the diaphram.
all done. :-)
I originally got the idea from Mathh from the uk site
