mori nv5000 bleeding charge tank

I am having trouble getting my knock out cylinder to extend all the way down so I can insert the retention knob in to the fingers of the drawbar. I have been bleeding the charge tank half the day. It only needs to go down another 1/8 inch. We just changed the Bellville washers and fingers. Has anyone seen this problem before? Do I just keep bleeding and adding oil some more?
Thanks Mercman

Yes. MDI mode-open bleeder, close bleeder, manual mode, tool unclamp/clamp a bunch of times, rinse and repeat. Now, if the Lucifer valve is failing/failed, all bets are off. Did you replace O-rings? Lots of grease? Was the drawbar shaft scored? Mori springs or aftermarket like Key Bellville? Aftermarket ones usually need to be deburred on the inside.