Pump Assembly

The distributor head, plunger and control spool are so precisely fitted to each other (actually lapped in) that they seal even at very high pressures. Small leakage losses are nevertheless inevitable, as well as desirable from the standpoint of plunger lubrication, and they are designed into the assembly. For this reason, only the complete pump assembly may be replaced - never the plunger, distributor head or control collar separately.