I don't have a lot of great pictures to include on this particular project but I wanted to share some things I learned through this process. Hopefully you guys might find it beneficial.
For reference, my gas tank started out like this -- Lots of overspray and undercoating. Heavy rust where the foam seal had been. Light rust internally.
For the exterior rust, I used Metal Rescue Gel to remove 70% of the rust. After a week of treatment, I pressure washed the tank and then used a rotary tool to remove the remaining rust. This worked really well.
For the interior rust, I thought about having the tank professionally cleaned. The shops I talked with wanted $400+ and were insistent on adding a tank liner. I thought I could do better on my own, so I bought 2x 5gal and 1x 1gal containers of Metal Rescue. Total cost was $230 shipped (less than what was quoted from shops).
My neighbors probably think I'm running a Meth Lab now because my trash is overflowing with these...
I leveled & supported the gas tank and then filled it completely with Metal Rescue. I then taped off the tank and let it sit for 7 days - the end result was a completely rust free gas tank! After draining the tank, I fogged it with 2-stroke gasoline to prevent flash rust.
Here is the tank after painting it and re-installing it...
So, now onto the fuel sender. My sender never worked and I learned why after disassembling it. There is a small nichrome wire that changes the resistance based on the float position. Its common for this wire to break and that's what happened to me. For my sender, I was able to resolder the wire (given the break position) but I also found the wire can purchased new from this vendor: https://jacobs-online.biz/nichrome_wire.htm I bought a foot of this wire and ended up using it to repair 2 additional senders I bought from the junkyard. I'll keep these as spares or sell them on.
When you service the sender, its important you remove all the varnish from the rails that support the float. This keeps everything moving correctly. I used acetone to clean the whole sender, inside and out.
The other thing I learned is that the screen on the fuel sender can survive zinc plating. Mine was rusty, so after soaking it in Metal Rescue for 24 hours, I had it re-plated.
Edited by Shawn Piper