Fuel tank leak

My RV-6A has got a fuel leak right on the leading edge of the tank. The leak is where the tank mates with the wing right on the front. Is there anyway to attempt to fix this before removing the tank? I have thought about reaching in there with pro seal thru the filler cap and pushing some into the corner. It appears that it is leaking right where the tank is formed on the leading edge. The blue stain starts right on the tip of the leading edge and you can tell the fuel runs down the lip where the tank is mated and drips down across the back. It never has leaked in flight and does not always show up while setting in the hangar, but over the last couple days of no flying the leak has really shown up...must be something with temperature expansion and fuel level in the tank. Be alot easier to fix if it was the "fuselage" side of the tank.

Any suggestions would be appreciated. Thanks.