Called HWH, they told me air will not completely come out of the system if the rams are connected to the slide. They instructed me to unbolt both ends of the ram from the coach/slide (not the hydraulics), then unplug the electrical connection for the lock & unlock pin solenoids to prevent any movement from the pins. Next run the rams in and out numerous times while they are not connected until they completely sink. Reconnect everything when finished and the air should be out of the system.
So far, so good
Chuck
P.S. HWH said this is how they bleed the system after servicing.