English to Spanish Tech/Engineering Mechanics / Mech Engineering

Hola a todos, estoy con una patente mecánica sobre un "método para transmitir o transportar materiales fluidos o semifluidos por medio de una bomba de doble pistón" y no entiendo bien a qué se refiere cuando menciona "forerun" que significa "preceder" pero en este contexto no me parece que aplique.

Ej:

"Valve 7 is a volume control unit for rod-side feeding-in of oil and provides that return running cylinder being a little faster than 'forerunning' cylinder as well as a compensation of oil conveying loss"
"When valve V5 is switched to the next operating position increased hydraulic pressure is delivered to the respective 'forerun' cylinder leading in an increased driving speed of the piston"
"Valve 3 is an unlockable double check valve, which is active during 'forerun' of cylinder A and return run of cylinder B"

Muchas gracias por cualquier ayuda!