To remove the tank, you will need to drain it and then jack up the rear of the car and put it on jackstands ahead of the rear wheels, remove the left rear wheel, remove the shield in front of the tank that is in the driver rear quarter panel, remove the lower end of the shock absorber on that side by jacking up the diff with a floor jack and remove the rear driver side leaf spring front shackle from the body (4 bolts/ 9/16" wrench) and let the front of the leaf spring drop as far as it can using the floor jack to control the drop (don't let it drop so much though so as to stretch the rubber brake line hose any significant amount), remove the lines to the fuel tank sending unit and vent, remove the two strap bolts to release the tank and then slide the tank forward and out of the rear quarter. It is a very tight squeeze, and you have to wonder how they were able to manage such a tight fit in the first place, but with patience, it can be done.
My 73 Monaco wagon had the wrong tank in it (it was from a B body Crestwood wagon) so I had to use my last NOS wagon fuel tank for these models (I enclosed a couple photos below of the new tank) and had to install a new sending unit. A photo of my wagon is attached too. These are great vehicles. I have to believe Chrysler Corp lost a lot of money on each one they built given their relatively low volume and the complexity and uniqueness of all the parts specific to this particular body style.
It was a perfect day this mother's day to do the changeover, so I included a photo of that as well.
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