Hi,
I've not yet used a tank cleaner/sealer myself, but am seriously considering it for both my TR4 and a motorcycle. The cycle especially needs it since it sat for many years before I bought it and developed some spot rust in the tank. Just enough of that sheds regularly to get into the carbs and plug the jets. I've cleaned them far too often! A fine fuel filter helped, but the problem still persists.
I know the TR4 tank was repaired after an accident. The side mounting bracket poked a nice hole in the tank, lucky it was less than half full so it didn't dump a bunch of fuel in the car and on the ground, and the car didn't go up in flames! I imagine the process of brazing or welding that repair has accelerated corrosion within the tank.
I've looked into the pluses and minuses of the tank cleaning/sealing process. What I've found is that, yes, it works. You first put a cleaner in the tank and slosh it around, let it do it's thing neutralizing rust, etc. Then an etching preparation is put in and sloshed, to ready the tank surface for the sealing coat. Finally the sealer is put in last and sloshed around to try to cover all internal surfaces.
Done right, I understand it works well, at least for a while. It's critical that each step be done properly and thoroughly.
I have heard several reports of the sealer starting to peel and causing system blockages itself, after 5 or more years. However, I don't know if that's due to poor application, or is in any way typical. I hope some others jump in here and tell us!
At least, it sounds like it's possible to buy 5 more years' use out of a tank before having to replace it. Whatever is used to seal has to resist all the detergents, alcohols, etc. put into modern gasoline.
Yes, the big TR vendors sell kits. But, almost any restoration specialist offers it, such as
www.eastwoodcompany.com or
www.por15.com. I'll shop around, there are probably many online sources.
Cheers!
Alan