Abstract: An improved method and apparatus is provided for detecting leaks in a bladder of a mold. The mold comprises a lower platen and an upper platen, and an inner cavity having an inflatable bladder contained therein. The bladder is mounted to the mold via one or more mounting rings, wherein the one or more mounting rings further comprises a vent passage having a first end adjacent to the bladder wherein the first end comprises an annular shaped groove; the vent passage having a second end in fluid communication with a valve, the valve having a first position connected to vent, and a second position connected to a pressure measuring device. A method of detecting leaks in a bladder of a mold having a gaseous inflation cycle and a deflation cycle is provided. The method comprises the steps of: creating a vent passage in a section of the mold in contact with the a bladder of the mold; venting said vent passage to atmospheric pressure; during a portion of the deflation cycle, sensing the pressure in the vent passage.