All those quickie solutions are only stop gap measures, the problems will come back. Do it proper. Do the four step process, remove the varnish (Marine Clean or equivalent), remove the rust (Metalready or equivalent, coat the now clean surface with zinc (done in the Metaleady process), coat the surface with POR-15 sealer (or equivalent, use good quality sealer that won't flake off later like my previously applied by rad shop job did). You have to take the tank out and weld in a bung hole to drain the tank so the sealer doesn't pool as the hole(s) are not the low points in the tank. POR-15 is said to seal pin holes as well. Or buy a new tank (if single hole) but it too will rust sooner or later.
When you remove the tank you can:
1. Turn the differential upside down to drain the oil and put fresh in (if your diff isn't leaking and don't need a new gasket)h.
2. Paint the axle, springs and links.
3. Replace the shocks if needed.
4. Replace the springs if needed.
5. Spray waxoil (or other undercoating of your choise on under side of car (above gas tank, axle and the many nooks and crannies.)
6. Replace rubber bushings with poly if needed.
7. Replace rubber brake hose with braided if not all ready done.
8. Paint the drive shaft while disconnected.
9. Put new rubber hoses on the gas line(s).
10, Replace the sender if rusty.
11. Replace the fuel filter (on FI cars).
12. Clean out the inlet pipe on fuel pump (on FI cars).
13. Polish the brake lines so their nice and shiney bright.
14. Replace any broken plastic fuel line holders.
15. Replace the fuel hoses to fuel separator (on N/A type cars).
16. Clean and lubericate the emergencey brake pivot points so it will work on a steep hill.
17. Replace the muffler if needed.
18. Never have to look at the back end again.
I did all the above (except for the if needed ones, they didn't) except for step 17. Guess what? I now need to do step 17.
TR7 Spider - 1978 Spifire - 1976 Spitfire - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra