Patent ID: 8365654

Claim:
A brake pump assembly comprising; a body defining a pump bore which includes a pump cavity and a piston bore extending from said pump cavity, a piston slideably received by said piston bore including a proximal portion adjacent said pump cavity and a distal portion opposite said proximal portion, an elastomeric seal mounted to said distal portion of said piston to slideably and sealingly engage said piston bore, said body defining an inlet and an inlet check valve disposed in said inlet for communicating fluid into said pump cavity; an outlet check valve disposed within said pump bore for communicating fluid from said pump cavity, a spring disposed within said pump cavity and extending between said outlet check valve and said proximal portion of said piston for biasing said piston away from said pump cavity, a peripheral sealing lip disposed at said proximal portion of said piston slideably and sealingly engaging said piston bore and extending primarily longitudinally towards said pump cavity to create a directional seal sealingly engaging said piston bore during a discharge stroke and selectively disengaging from sealing engagement with said piston bore during a suction stroke for depressurizing fluid accumulating between said peripheral sealing lip and said elastomeric seal, and a projection extending from said proximal portion of said piston and spaced radially inward of said peripheral sealing lip and extending primarily longitudinally towards said pump cavity to define an annular channel therebetween for receiving said spring.