Abstract: A composite piston for an automotive air conditioning compressor is provided having an aluminum shank or piston rod, a reinforced plastic piston head and a steel ball for engaging a socket plate or the like. The shank has a distal end that has a slight reverse taper and a knurled surface for providing attachment to the plastic head that is molded thereon. The proximal end of the shank has a barrel to which the steel ball is press fitted. The shank is provided with a first collar adjacent the knurled distal end of the shank and a second collar adjacent to and intermediate the first collar and the proximal end of the shank. The first collar provides a seal for the mold cavity into which plastic is injected to form the piston head over the knurled surface of the shank. The second collar provides a support for the press fit operation of the steel ball onto the distal end of the shank.