Tilt/ Trim Questions

Not sure if this is the right place but I have a few questions. I recently rebuilt my tilt and trim, all new orings, scraper seals, everything. Started bleeding the system. Process is fill with fluid, cycle trim all the way up and down a few times, open fill cap to purge the air. So far I've gone through 5 tubes of fluid. I'm still getting milky fluid (air bubbles) coming out, when trimming up I let off the button and the motor continues to rise like pressure is continuing.
Questions are
Do I need to continue to bleed the system? Did I mess something up? Does it seem like it's sucking air somewhere?
I did remove the small 1/4 inch drain plug on the bottom and put it back in.