[wedged]

at the rear of the mid section there is a disc type check valve that has a small plastic valve on front of it. the disc check valve is about 3/8" in diameter and about 5/16" thick. one side has a metal cage/retainer the other side has 4 holes- one in the center surrounded by 3 holes. What end of the disc should be go into the bore it fits in ? the 4 hole side or the side with the retainer ?