an improved caster assembly is provided having a load - bearing bushing rotationally disposed in a caster body and including at least one grooved recess about its perimeter wall . as the bushing rotates relative to the caster body , the grooved recess acts to dislodge dirt and particulate matter disposed between the outer surface of the perimeter wall of the bushing and the inner surface of the bore in the caster body . rotation dislodges the particulate matter where gravity causes it to fall downwardly away from the bushing where it is displaced from the caster assembly through an open end of the caster body or suitable debris outlet .