A piston and ring assembly operative within a cylindrical bore wall to retain fluid to one side. The piston has a side wall for movement along the cylindrical wall and has one or more spaced grooves in the side wall, each groove defining a pair of interior groove surfaces spaced apart a uniform distance; at least one sealing element presenting a pair of opposed surfaces operating between and along the pair of groove surfaces, the sealing element being capable of engaging the cylindrical wall, the spacing between the opposed surfaces of the sealing element and the pair of interior surfaces of the groove being no greater than ten microns; and a solid film lubricant mixture coating the groove surfaces and the opposed surfaces of the sealing element, whereby surface adhesion of the fluid, present in the spacing, inhibiting migration of such fluid through the spacing and flutter of the sealing element, in said spacing, being essentially eliminated.
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