This all started with an off-side ( right hand) fuel tank that was weeping from the sump plug. I should have just put a wrench to the plug and given it a yank in the tighten direction, and been done. Anyway, several hours later, both valences are off, both tanks are drained, and I have 1: replaced the failing right hand fuel level sender. 2: found that both sump plugs have common steel screws in the drain holes, which are terminally rusted in place, 3: driver’s side tank has been replaced by a previous owner. 4: the right tank is the 44 year old original. 5. in the course of messing around with things I found the fuel outlets will weep if you jiggle them where the tubes go through the mounting plate.
I have new plugs and assorted gaskets in hand or intransit.
I started out thinking I needed a tank, but it appears the original problem was just a hard deteriorating gasket. You’ll see from the attached photo what came out of the bottom of the tank, about a 1/4 cup or less of rusted steel. A local shop is going to fix the fuel outlet. It’s obvious the piece has been worked on before in a manner the English term “a bodge”; a local welder is fixing it.
So, I am asking for advice and opinions. A tank is about $300 with shipping. The POR-15 Sealing kit is around $100 + the time. Either approach includes is going to include the additional time for removing and installing a tank.
What would you do?

 

What does the inside of the left tank look like? If the small drain screw is also rusted in place, you may have two tanks in bad shape. If it were me, I would buy a new tank instead of prepping the inside of the old one, buy the sealing kit and hope the sealant completely covers the inside of the tank. If the fuel outlet(s) are so rusted that you can wiggle them and cause a leak, I wouldn't trust anything about that tank. How much will the welding work cost?

Dave

 

In my opinion, $300 for a new tank is money well spent. Fit and forget; it’ll should last 40 years like the original.

Both my tanks were rusty and I changed them for new ones. I changed the left tank last year and ran on that only, then the right tank this year when funds allowed. It was rather more expensive for me as I live in Thailand and had the tanks shipped from UK. It was about £300 including freight for the last one but I got clobbered 30% import duty then 7% VAT on top so about £420 all in for one tank. I thought about asking a local fabricator to make one but the tanks are complex shapes on these cars and need to be exactly right to fit in the cavity so didn’t go down that route.

I think the POR coating is really just a temporary fix as the steel is likely to continue to rust unless you can get a perfect full-coverage seal on the entire surface of the inside, which would be very hard to achieve I think.

 

I think the previous owner reused the original sump plug when swapping in the replacement tank. They both show signs of original undercoat and the stamping on the head of the hex head screw is identical.
The newer tank only gave up three or four small flakes of rust; the bottom was clean. I trust its condition. Unlike the original it’s painted on the outside and shows no external rusting on the seams. I’m thinking I’m in this far, a replacement tank is in the future.