I've used POR-15 on both of my classic Motocycles and was very happy with the results. I plan to use it again on my Mini's tank. The directions were straight forward, take your time and it should be good.

My 1st tank proved to be solid and after removing rust and debris the Por-15 made it pretty awesome.

2nd tank appeared to be in good shape with some internal rust and debris. I cleaned it out, everything looked good no damage but after sloshing the Por-15 around and getting all the areas it appears I had 1 very small pin hole that has been sealed up with the Por-15. I spotted it because the Por-15 bubbled out of the hole. I circled it so I can keep an eye on it. It's been 4years with no issues.

You can buy a tank kit which has the cleaning agent, prep agent and Por-15 sealer. They make a car sized kit and a Motorcycle sized kit as well as selling the stuff individually and in various sizes. I'll probably get a motorcycle kit with an additional smaller size of the Por-15 because I have a larger than 5.5 gallon tank. 

I interpreted that post as the tank liner failed at the level of fuel in the tank.

What?

my moke came with a religious tank you know it was very holy went to eastwood follow the directions to the letter after sitting over the winter with a half of tank. finish lifted at fuel level

Another option to look into are these guys:
www.gastankrenu.com/index.htm

Craig, my problem was the sluffed off tank liner material pluged the fuel supply pipe before the pump's pre-filter.  I could drive about 1/2 mile (until the float bowls went dry) and then I'd have to sit with the engine off and ignition on to allow the pump to trickle enough fuel in to drive another 1/2 mile.  It was a long drive home.

+1  on POR15

I think the kit included the cleaning and prep chemicals and some of the patching gauze, which worked very well on the filler neck.

 

I punched out the screen.  No problems so far.  Good fuel filter before and after the pump. 

Chuck, I took the screen out because I was advised (on one of the instruction sheets) to do so.  

Do not take the screen out.  Coat the tank as normal and when you are ready to put the tank aside to let the coating cure, connect a low pressure air line to the tank's pickup tube so air is flowing into the tank and keeps the screen filter "open".  

If I had left the screen on my LH tank I could have gone a lot longer with the failing POR before having to strip the tank.  As it was, a strip of POR was in the output leg of the "T" connecting the LH and RH tanks.  No fuel could get to the pump.  

Only one mention (from Doug) about removing the inner screen. What have others done?

I used the POR system back in 2004 in both tanks and it still looks great with no signs of deterioration.  The Marine Clean with a handful of nuts and bolts sloshed around in the tank removes any loose or flaky rust, and the metal prep has a zinc coating that acts as a primer for the sealant to bond to the tank.  Sealer is applied after drying out the tank completely.  I used a heat gun for this purpose.

After treating, I could see the POR coming out from the pin holes along the seam of my tanks.  I then restored the outside of my tanks, primed and painted and they still look brand new inside and out.

I have lined several tanks using different materials (Kreem (Eastwood), POR, and Red Kote).

They all require cleaning and prep work just like painting.  The prep methods are almost identical.  Kreem uses MEK for a solvent and prep so it is a bit more dangerous.  OR and Red Kote are easier to work with.  Kreem has been around forever and you will find lots of stories about it failing.  That has not been my experience (yet).  After about 10 years the Kreem coated RH tank in my Mini is still doing well.  The LH tank was coated with POR.  It lasted 8 years and failed last fall.  Though the prep method was the same as Kreem, rust bubbles started appearing under it.  Eventually some material sluffed off and plugged the fuel pickup tube in the bottom of the tank (the internal tank filter screen had been removed).  I replaced the POR with Red Kote after working for a month to strip the old POR.  I chose Red Kote after discussing it with Todd Miller and finding very few complaints about it on the web.  So far, so good... but it has only been about three months now.

So why did I try POR after good results with Kreem?  MEK.  I did not like working with Kreem and it leaves a white coating that quickly discolors to orange or caramel after exposure to gasoline.  The POR leaves a nice looking metalic finish in the tank.  It doesn't discolor much and looks like metal.

After the POR failed I considered using Caswell's epoxy liner kit but became concerned about a few reports where the epoxy failed or caused other damage.  It was hard enough getting the POR out of my LH tank, I figured removing epoxy would be even worse if the Caswell coating ever failed.

So which would I use today?  The POR looks the nicest and lasts a long time.  Kreem worked for me but I hated dealing with the MEK.  Caswell has a good reputation but I cannot imagine trying to remove the epoxy should the tank ever need lining again.  If the Red Kote holds up as well as its reputation I will probably use that in the future should I ever need to.  

//www.hirschauto.com/Gas-Tank-Sealer-_-Repair/products/4/

I've used this and the radiator shop we use have used this for at least 30 years.

Never used to "seal" a leak. Repair the leak (weld,solder) and then treat the tank.

No rust inside we scoped it. I think the welding was not so good. Over the winter storage I only lost ounces I could smell it but couldn't find any wet spots until I removed it to replace the shocks. 

I used the POR15 sealer also.......You only need the Motorcycle kit if doing an original 5.5 Gallon tank

//search.eastwood.com/search?w=gas%20tank%20sealer%20kit

It has been several years now since I have used a gas tank/sealer kit.  (read that as 22+ years ago I used a kit from Eastwood).  Before you seal it you need to clean it and remove rust.

i used the POR gas tank sealer, it has been 4 years and no problems, 

As the title, the lower seam on my tank is weeping google searching gives a lot of opinions of various stuff to put in the tank. Anyone had sucess or otherwise with any of them?