An ultrahigh pressure pump includes a frame including at least one
radially-extending member having an outer frame pivot disposed at outer
end thereof; a crank rotatably mounted in the frame and adapted to be
driven by a power source and a crank pin offset from a rotational axis of
the crank; and at least one radially-extending telescoping pump
subassembly having inner and outer ends. The outer end of each pump
subassembly is attached to the outer frame pivot for pivotal swinging
movement thereabout, and the inner end is pivotally attached to the crank
pin. The pump subassembly operates substantially free from side loads on
the piston rod and has a long component life.