we need pictures to better understand whats going on.
you wont be able to push the rod in by hand it takes a lot of force and you may end up bending it if you try.
the arm inside the case should move up and down in time with the ball bearing part in the middle.
if its gunked up cover it in petrol/diesel/white spirit and attack it with a fairly coarse paintbrush to clean it out.
then try bending and moving the arm by hand, give it a lil wiggle.
if i remember correctly the screws holding it on are made of cheese and torqued to 50 million newton miles.
you wont be able to push the rod in by hand it takes a lot of force and you may end up bending it if you try.
the arm inside the case should move up and down in time with the ball bearing part in the middle.
if its gunked up cover it in petrol/diesel/white spirit and attack it with a fairly coarse paintbrush to clean it out.
then try bending and moving the arm by hand, give it a lil wiggle.
if i remember correctly the screws holding it on are made of cheese and torqued to 50 million newton miles.