Excavator Parts SA8230-03340 SET PLATE RETAINER FOR MAIN PUMP FITS EC55B AP2D25 Pump Parts Hold every piston shoe captive and prevent separation off the swash plate. Under high pressure impact during cylinder block high‑speed rotation, spring force pushes the cylinder block to press piston shoes firmly against the swash plate inclined surface. The set plate encircles piston shoe tails to restrict outward flying motion, guaranteeing continuous fitting between piston shoes and