Do I need a pre-pump filter? If so, is there a specific filter I should use?

Filtration is extremely important when using Flight Works micro gear pumps, as the components and clearances are extremely small and minuscule particulates can cause damage if not properly filtered. A filter with a 25-50 micron rating or better should be installed before the pump (the finer the better). In closed-loop systems, installing a filter after the pump can also be beneficial, as it will prevent any “break-in” period from contaminating the system.