Excavator parts AP2D25 VOE 14520404 Piston Shoe Set Of 10 Pc For Hydraulic Pump Parts Force Transmission and Angle Self-Adaptation Inside the cylinder block, the piston moves back and forth linearly, whereas the swash plate is fixed at an inclined angle. Connected by a spherical hinge, the piston shoe can swing freely matching the swash plate’s inclination and steadily transmit the piston’s axial thrust to the swash plate. Removing the piston shoe would let the piston ball