Gas tanks R & R is fairly
simple. If it leaks or rusts, get rid of it and replace
it. Yes you can paint them, but the problem is the
inside. Gas tanks are coated with Zinc. It is
galvanized. This is for galvanic reaction to prevent
rusting. There are long explanations for this, but the short
explanation is the zinc is sacrificed or wears away preventing the
metal on the tank from rusting. Once the zinc is gone, you need
to re-dip the tank or get a new one. Rust happens fairly quickly
after the zinc is gone.
Here is an example of my filler tube. Similar to the tank they
are usually galvanized. This one is 40+ years
old. Looks fairly good on the outside, even better if I
cleaned it up. Most all the galvanized coating is gone.
The problem is not the outside, it is what is happening on the
I don't want all this rust sediment going into the tank. Two
choices. Clean up this one and get it re-galvanized or buy a new
one. In this case, the new one is cheaper, much cheaper so
on with the new part.
Those new replacement fillers, they come close, but will need some work
to align and get the cap sitting right. In my case the
overall bend was off by about 3 degrees. Good thing the new hose
to connect it to the gas tank was longer than I needed. I needed
the extra length to get the adjustment right.