It is a pain to drag the thank out.. but it can be done. You don't have to rip the plane apart. You do have to remove servos (usualy) and might have to knock the servo tray out. [:@]

If you were smart (or properly advised...) you added packing tape on the tank in a manner to give you a pull tab to grab. Makes puling the tank out MUCH easier. the hard part is getting hold of the tank. It is t a tight fit, but it slides back fine once the stuff is out of the way under the cockpit.

T get the fuel lines back in... plug the lines onto some nyrod or something and pull them through the firewall with that. (you may have to remove the engine to have good access to do that.[:@] )

A total pain... but if you have a hole in the clunk line inside the tank... you HAVE to pull the tank.