I would like to replace the locking fuel hatch door on my 1990 Southwind but can't find a door that is the same size. OD: 8 5/8"w x 9 3/8"h. ID: 5 7/8"w x 7 1/8"h. Lots of different doors on lots of different sizes but none that fit this footprint. Actually, just need the hinge pins and the door but will take the whole assembly. Maybe someone has one these "laying around" on an old RV.
I ran into the same problem with my city water fill door. It is very similar to your fuel door. I can't find a replacement anywhere. There are some that look quite similar but have enough differences that they don't fit. I did as you suggested and cleaned and fixed what I could. I did manage to find a near replacement at an rv salvage lot, but, again, it has enough difference that it doesn't fit the space.
I have the exact same one on my 89 Winnebago Chieftain. I know they are available since I was going to get a new one because mine looks the same as yours inside. I think maybe I saw the replacement in the Winnebago catalog. I will try to remember to measure mine tonight when I get home.
Fleetwood doesn't have very good documentation on their vintage coaches but Winnebago seems to. I was cruising http://winnebagoind.com/product-resources/product-information, and there is some very detailed diagrams and part numbers for older coaches. I tried to find a fuel hatch door but don't know the particulars of your coach. Maybe you would have a better shot at tracking it down. I want to replace mine because the hinge(s) has broken. The black stuff on the inner part is just dirt and gas that can be cleaned out.
I think I found a door assembly. It's manufactured by JR Products(model #31102-A) and you can check it out at http://jrproducts.net/index.php/catalog/load_product_list/Fuel%20Hatches/Fuel%20Hatches/ It's available from lots of sources including eBay for $30-$45 although some suppliers like Amazon don't have the correct outside dimensions. The unit is paintable so you can match the existing color, in my case a light almond.
I had originally thought it was just the door and outside bezel, but it's the whole unit that the gas filler pipe mounts into. There will be a little extra work detaching the gas filler pipe but it looks straightforward on my coach.
Should just be two or three screws next to the pipe with the cap off and then the assembly will lift off of the pipe. Put the cap back on until you are ready to reassemble so nothing falls in.
Yes, mine is held on by 3 pop rivets but easy to drill out and replace with small machine screws.
Maybe that explains why I have extra holes in mine, it may have been riveted and then drilled for screws. Mine are Tec screws, self tappers need no threading or nuts. Just a drill with 1/4" a nut driver bit.