We will need more details on what you have.
top hat pull rod or self centering (cone)
side thrust release bearing - must be fitted the right way around.
If you fitted it the wrong way then you would be forcing it apart when operating the clutch and wouldn't get the lift.
When you say "it wont stay there" - what changes ?
Does the big nut tighten or get slack ?
You seem to be able to re-adjust and go again - do you loosen the nut or tighten it ?