Mine were jammed up tight, wouldn't budge.. Pushed, pulled, it didn't matter.. They wouldn't move.. I laid a small bead of WD-40 around the rod where it meets the plastic.. Waited a few minutes to let the WD run down the rods.. And they broke free with very little effort..
PS.. You don't have to drown them in WD, just a few drops to run down the rods..