Right, I think I know what you mean. So, what cylinder/piston set are you using? If it's the stock one then a good test is to remove the cylinder and with a screwdriver pull the piston back about an inch, put your thumb over the nozzle and let go. Does the piston blow out or hold? if it blows out, air's escaping. (With a Laylax one it's designed to do this as the flimsy O ring is designed as a vacuum expanding seal). Either the O ring is crap or the head is leaking air, you can PTFE tape it to help.
In terms of the rough pull/push, again what are you using? Could be the bolt stop grinding on the cylinder.