... include internal (rod seal), external (piston seal), symmetrical or axial seal. With the internal (rod) seal, the seal is ... seal (single acting) because it can seal in the one axial direction the application is moving. 7) However, a reciprocating ... housing bore diameter or seal outer diameter, the axial cross section and the radial cross section.Hydraulic Seals – Type Piston SealsRod SealsBoth Piston ...