Doc my friend you are indeed a wealth of information. Absolutely 
amazing!
Charlie
 
In a message dated 6/21/2006 3:46:33 PM Eastern Daylight Time, 
AMC74HORNET@xxxxxxxxx writes:
Hornet's have no expansion tanks. The tank is vented to a roll 
  over
valve above the rear axel on the drivers side frame rail and vented to 
  a
charcoal canister under the hood which saves the fumes until the 
  engine
is started and then they are sucked into the carb. Form 
  personal
experience I have seen the main metal fuel line that goes to the 
  fuel
pump on the pass side of the car rust out above the middle of the 
  rear
axel. The metal vent line that is soldered into the tank that the 
  rubber
hose connects that goes to the roll over valve I have the solder 
  break
loose from the tank. The rubber "O" ring that seals the fuel tank 
  sender
leak along with hair line cracks at the sender mounting flange in 
  the
gas tank. Also as strange as it seems the top of the tank can 
  rust
through when dirt holds moisture between the tank and the trunk floor. 
  I
would also replace every rubber fuel line in the whole car. All of 
  the
above problems I have encountered in my 2 Hornet's and other 
  friends
Hornet's and Concords that I have worked on in the last 30-+ years. 
  I
eliminated the charcoal canister and the lines in both my Hornets 
  and
made a fuel tank vent like the late 60's Rambler Americans had but 
  kept
the roll over valve. Also the 22 gallon gas tanks installed after 
  74
some time in place of the 16 gallon tank is still available for 
  around
225-250$ since they are the same as an Eagle and fit the earlier 
  16
gallon tank cars with only minimal modifications. I have 2 of the 
  newer
22 gallon tanks in both cars. If you have a tank problem don't 
  waste
your time on any of them sealer kits. Been there done that, I 
  ended
buying and installing a new tank anyway. A new tank is well worth 
  the
money in the long run. The sender locking ring is also available 
  along
with the tank from your local non-chain auto parts store and 
  Kennedy
American has NOS senders.
"Doc"