A hydroform seal assembly includes a seal housing and an annular nozzle carried by the seal housing and sized to insert into a tube end. A first actuator moves the seal housing to insert the nozzle. A plurality of jaws are carried by the seal housing and are movable radially inward into clamping engagement with the tube to clamp the tube onto the annular nozzle. A cam bushing is movably mounted within the seal housing, surrounds the jaws, and has cam surfaces complimentary with cam surfaces provided on the jaws so that movement of the cam bushing relative the jaws will cam the jaws radially inward. A backup cam is movable within the seal housing. The cam bushing and backup cam have complimentary cam surfaces by which movement of the backup cam will forcibly move the cam bushing relative the seal housing. A second actuator moves the backup cam.