ACDelco Wheel Cylinder - 18E394 Part #: 18E394 Line: ACD ACDelco Wheel Cylinder 1 Year Limited Warranty Material: Cast Iron Hardware Included: No Bleeder Screw Cap Included: Yes Bleeder Screw Included: Yes Inlet Thread Size (in): 3/8 Inch Inlet Thread Size (mm): M9 Wheel Cylinder Bore (in): 7/8 Inch Wheel Cylinder Bore (mm): 24mm Show More Show Less