Abstract: A process for inserting a piston pin locking ring, particular slotted snap ring, into a locking groove of a pin bore of a piston. The piston pin locking ring is radially pre-tightened and reduced in size in a first step in such a manner that its outside diameter becomes smaller than the inner diameter of the pin bore. The piston pin locking ring is subsequently introduced in the pre-tightened state into the pin bore without contact and without contacting the inner wall of the pin bore and is brought in position inside the pin bore in the area of the locking groove. Then the piston pin locking ring is freed by a relaxing and loosening of the tightening force and by springing into the locking groove and is thus fixed in place.