A Hot Toddy for the Tank

Despite their reputation for durability, old VWs were only ever a 'cheap car.' That means that while the design was excellent (and has been proved itself world wide) there are material science items where corners were cut. Like the fuel tank.

American Manufacturer fuel tanks (the big three) were terne plated, which made them much less prone to rust out. VW skipped this step. In a Beetle, this is an annoyance, not a crisis. Open the bonnet, clamp off a few connections, four bolts removed and the tank is out. New tank goes in the same way, and the whole affair will take an hour if you drag your feet and stop for beer frequently.

Engine & Transmission out, firewall off, fuel tank
drained (GHACK!) unbolted and removed.

But the bus stuffs the fuel tank over the transmission, and requires the engine to be removed to get to it. (Though there are some circus acrobats who have found ways to avoid taking the engine out to get the tank out, the efforts to avoid an engine drop are almost worse than the drop itself.) There is also the matter of the fuel tank itself not being reproduced where the world market can get to them. So all of the tanks out there...that's all there are.

I decided to squander a fortune ($25) and buy a fuel tank at a VW show that was dry and in decent condition on the assumption that I'd rather start with a slightly scaly dry tank than the gag inducing tank that is currently in there. My plans for the current tank are simple: drain and dispose. My plans for the new tank are more complex: refurbish and install.

The refurbish part is the tough one. Yes, you can take your fuel tank to a radiator shop and have it 'hot tanked' or 'boiled out' or other euphemisms. Essentially, they're giving it a full immersion baptism in hot acid. Then hauling it out, hosing it off, and handing it back to you, not quite dripping wet with flash rust starting to appear, but almost. This will not stop rust, (no terne plating, remember?) but it will give you a place to start from to chemically coat the tank so that you won't be doing the same operation again in a year.

Some how, I think this fuel sender has had it.
13 years suspended over a noxious soup in that tank.

You will pay a shop about $200 for the privilege if you can find a shop even willing to do the work. The replacement culture reaches even to independent shops who would rather sell you a Chinese product made to minimum specifications than do the labor intensive work involved in refurbishing your tank. This is simple business logic: labor costs more.

But my labor is a double win for me: My labor costs heartbeats (which I may have more of than dollars) and when I'm finished I am richer...in knowledge and self-reliance. And can perform the same feat again, faster, probably better, and if working for someone else....for cash or chattles. Or barter for something they're good at. And there are no 'aftermarket' or 'reproduction' fuel tanks for the Bus. (UPDATE! Bus Depot is now carrying a replacement fuel tank; fit, finish, and source is unknown.)

The state of my DRY replacement tank after water & roofing nails spent some time sloshing around in there, before the acid cleaning. This is pretty good. The tank I took out was a retch inducing corn-dog inside by comparison.

So a fuel tank refurb is a cheap exercise for me, having done it once before on my VW Super Beetle (1302). I learned from that one and I have better methods now. Here's how the cost breaks down:

• 1 gallon Muriatic Acid:  $7.50
• 1 aerosol can Rustoleum Painter's Touch: $7.50
• Quart of US Standard Fuel Tank Sealer & POR15 Prep&Ready (Phosphoric acid): $50
• 10 boxes of Baking Soda: $10

$75 for materials (and I believe I still have some of the paint from restoring the Super Beetle) and a cautious set of practices gets me a 70% discount. Here's how its done....

After the dry, slightly corroded replacement tank had all of the rust scale
scraped off of the interior and Metal Ready (aka Prep-n-Ready), I needed to get the
inside dry again...fast! so the Metal Ready can work best.
One kerosene heater to the rescue. The tank was dry within an hour.

But first a word from our sponsor: Acid is dangerous, can kill you in subtle and quick ways, and should be treated like handling a live rattlesnake. The rattler can be useful to you if you know how to use it, but has no tolerance for clumsy handling and will kill you to show its disapproval. Acid is the same way. I'm describing what I'll be doing, I'm not giving you instructions: go look them up somewhere else, say OSHA or some-such. But don't follow my example.

With that out of the way, here's my procedure:

Day 1:

1. I'm outside, but won't be disturbed by pets, kids, or other ungovernable persons. Lots of fresh air.
2. I have set up a pair of saw horses and will later make a table of some material that I don't care about that will support the fuel tank.
3. My tank has a little scale in the bottom, so a gallon of boiling water, a cup of detergent (Tide), and seven pounds of unused and unwanted nails go in.
4. Now I rock the baby back and forth for an hour. (Since I haven't let the acid out yet, others can spell me on this part. Just make sure no one drops that tank on their foot, or this party will move to the Emergency Room before it really gets started.)
5. Back and forth, back and forth, back and forth, until the arms ache and the grinding sound of those nails across rust makes you wince. The hot water will turn ochre colored as the rust comes off.
6. Dump. Flush with clean watch. Inspect rust scale. Repeat until all of the scale is OUT.
7. When this part is done, I'm done for the day, too. Playing tag with the Acid is not something to be attempted when tired. As a last matter, so I don't have to remember tomorrow, plug all but the fuel level sensor outlet for the tank (inlet, outlet, two vents on top, fuel fill neck.)

Day 2:

1. I fill a pail with 2 gallons of cold water mixing three of my baking soda boxes into it. This is for emergency chemical quench, and might let me off with a burn, rather than sending me to the hospital. When you feel it start to burn, its already too late to mix a batch of antitoxin, just like that rattle snake bite.
2. Set aside a second pail, empty.
3. I run a water hose to my working location, with a trigger nozzle on the end. Crack the water valve just enough to provide perhaps 2 gallons per minute, and if the nozzle has spray styles, set it to the least restrictive one so that water come gently burbling out, never a spray that might cause a splash.
4. I don a full body outfit covering every scrap of skin I would like to keep attached to my corpus. (That includes safety glasses, so my eyeballs will come home still working.) If it isn't covered, its fair game. Rubber gloves, the industrial kind, not exam gloves.
5. Fill the tank half way with water. Water first. Water First! WATER FIRST!
6. Pour in 1/4 of the gallon of Acid, while reciting Novenas. Do not GLUG it in: a nice, happy, laminar flow.
7. Recap all acid containers. Set them out of the way.
8. I S-L-O-W-L-Y rock the tank to let the acid mix with the water. If the water and acid don't mix, the reaction of the acid can cause it to boil, spattering my tender hide. So pay attention!
9. When there is a nice mix of water and acid cooking, fill the second bucket with water from the hose, and slow add it to the tank. Repeat until the tank is topped up. Cover but do not seal the tank so the O2 being produced can escape.
10. Get out of the clown suit carefully, assuming that there are errant drips of acid on it. Straight into the washer, and while it gets washed, into the shower to rinse your own hide. This is taking an extra 15 minutes both to soothe the nerves, and to rinse the hide.

Great. Now I have 14 gallons of acid in my back yard that I have to get rid of.


Day 3:

1. Having left the brew to simmer overnight, it now has to be disposed of. Reminder: it will look and smell awful. Back into the clown suit. 
2. Using a disposable transfer pump (don't even think about suck-siphoning!), start draining the tank. 
3. Don't even think of trying to move it manually, full of water, the beast weights at least 130 lbs. 
4. Drain the tank to the rear fence were it isn't going to be disturbed by children. 
5. When empty, rinse the tank with clean water
6. Dump in Prep-n-Ready (Metal Ready).
7. Rock heavily on the sawhorse to splash PnR against all surfaces inside.
8. Dump the (hopefully) unused bucket of premixed bicarb on the place where you dumped the dilution, and follow it up with powdered bicarb.
9. Now we're done with the acid, so the clown suit can come off.
10. Perform several 'splash and rock' events with the PnR over the course of the next hour.
11. Drain PnR back to its original container
12. Remove all plugs
13. Fire up the kerosene space heater. Place the tank on top it, insert a hair dryer on air dry into the fuel neck and give the tank two hours to quickly evaporate off any liquid in the tank. The steel tank will be scalding hot by the time its done evaporating out, but there can be NO water in the tank. I'm cooking it over the space heater to hurry the process along and complete the sealing bits in one day.
14. Put on gloves that will let you move the hot tank back to your outside workstation without frying yourself. Set it up on a tabletop between two sawhorses.
15. Re-insert the plugs in all orifices but the sender. Sealed up tight.
16. Dump in 1 quart of tank sealer and seal up the sender hole.
17. Rolling the tank around its long axis, wrap it in a long strip of carpet as long as the tabletop. Bungee the wrap around the roll. Now the tank will be easier to roll and handle.
18. Roll the tank around so that all orientations are passed through, and the whole tank interior will have been coated. 10 minutes.
19. Remove the carpet roll, and dump the remaining sealer, leaving it to drain for 30 minutes in an orientation that will leave no puddles in the tank.
20. Hang the tank from one tube and give it a coat of Rustoleum. Let dry for two hours.
21. Move the tank inside and put the hair dryer back on it. it will need to cure for three days.

Fin

Yes, there are a lot of steps here. But having followed them, I will KNOW that the tank is ready to go into service, no matter what engine it is servicing.

Finished tank, sealed inside and recoated outside. And ready for many more years of service.