I've just started to look at clearing the crud from the fuel tank which has stood untouched for 40 years. I've managed to remove what appears to be rust by putting a gallon of fuel in, swilling it around, and tipping it out and repeating. (This is the right hand plastic tray in the photo.
I then took the fuel level sender out and scraped out what I could of the tar like substance, that's the pie tray in the photo. The outlet tube is now clear but there's still a lot of the tar like substance in there, (I've bought an endoscope so I can do a proper inspection).
Any recommendations as to what to use to break down the remaining tar like deposits?
I would be tempted by sodium hydroxide (caustic soda) pellets and pouring in a gallon of hot water. Be aware this is nasty stuff, very good eye protection and indeed skin is essential. When the hot water hits the pellets it get much hotter, so make sure they are tipped to one side of teh tank away from where you are pouring the water in. Maybe a mugfull of pellets to a gallon of water. You could swich that around once it has been left for a few minutes, and then a nylon brush or scourers to give it a scrub up. Bits of metal rod to greatly extend your reach.
You may need to repeat and leave it to soak overnight.
Once that gunk is cleaned out, if lots of rust some brick cleaner mixed 50/50 with water and some nuts/bolts chucked in, swish about or better attach to a cement mixer, rinse, then some phosphoric acid to kill any remaining rust.
That would be my approach, others may have better ideas.
Frost restoration do a kit specifically to clean, protect and coat the inside of the fuel tank.
I have used this successfully in my own car doing this over 20 years ago
Trevor
75 Sprint in Magenta called GunGaDiN GGD944N
2017 Jaguar XE R-sport
Then add a coat of POR15 tank seal to stop it coming back.....
I did mine a while back & its working a treat at the moment. it even filled pinholes
in the bottom. Have to follow the instructions carefully to get a good result.
