A magnetorheological (MR) piston assembly includes an MR piston, a rod, and a guide member. The guide member includes an MR fluid passageway and is attached to at least one of the piston and rod. A perimeter of a projection of the guide member onto a plane perpendicular to the longitudinal axis surrounds and is spaced apart from a perimeter of a projection of the MR piston onto the plane A damper includes an MR piston assembly and a tube. The piston assembly includes a piston, a rod, and a guide member. The guide member includes an MR fluid passageway and is attached to at least one of the piston and rod. The guide member diameter is greater than the piston diameter. The tube surrounds and is radially spaced apart from the piston and surrounds the guide member, wherein the guide member makes sliding contact with the tube.