the clunk in the tank might had gotten sholved forward during
the landing, therefore the fuel line might be pinched.

i usually hit former #2 (behind landing gear)
with the palm of my hand as i swing the fuselage down
to un do kink on a plane with the fuel tank area glued and enclosed.

you can grab the nose of the plane and swing the fuselage

when building a 4 star . i usually make with a hatch option.
becuase of this problem. it's an easy fix with your 4 star
even if it's glued.

sometimes if foam or padding is not installed in the tank.
and depening how the line is routed.
the tank gets sholved forward. a kink is develope between
the tank and firewall