ARO PP20A-AAS-AAA Pump Part Exploded View Diagram & 2" Ported Powder Transfer Repair Parts PDF Manual. Air Section Service Kit: 637421, Fluid Section Service Kit: 637309-AA, Major Valve Service Assembly: 637374-7, Spool Repair Kit: 118597-2 Available. Replacement Diaphragm, Seat, Balls, O-Ring, Seal, Rod, Manifold, Washer, Bolt, Nut, Gasket, Sleeve, Screw, Pipe Plug, Bushing, Center Body, Plate, Spool, Ground Lug, Valve, Tube, Muffler.