Gas tank cleaning and derusting

[Spokes]

I saw earlier in the forum threads a question about cleaning the old fuel varnish from a cycle gas tank and removing rust. I would like to offer a solution to both tasks. I also use the varnish removal technique to remove oil varnish from my engine rebuilds. When I assemble my engines they are clean as new.

Before you begin you should protect the paint on the tank. (or not if you don't care) A thin layer of wheel brearing grease will protect the paint if some of the derusting or varnish removal solution spills on it. When your finished, remove the wheel bearing grease 1st with wd40 then with a good auto wax.

Tank varnish or engine part varnish. Buy Meguiers (sp) CHROME CLEANER.
or any chrome cleaner that lists ammonium bisulfide or bifloride on the label.

Fill the tank with boiling water (of course plug any holes) and add 1 to 2 pints of said cleaner. Let stand for about an hour and the varnish will dissolve. Rinse with water and repeat if need be. You may get flash rust, if so, a spraydown with PB Blaster will stop it .

Rust Removal. Buy a product called Milkstone Remover and Acid Rinse from your local Tractor Supply Store (it's Phosphoric Acid) or Phos & Etch from Home Depot (Same stuff but has a rust inhibitor in it)

Again, plug any holes and protect your paint as above.

Fill the tank with warm water (hot tap will do) and add a quart to the tank. You may get some foaming. Leave the solution in the tank for about an hour or two and rinse. You may not get flash rust with the phosphoric step.

These are the two techniques I use and it works like a charm. If you want to remove rust from the outside of the tank, and you have rust inside the tank, add 1 gallon of either phosphoric acid product into a tote large enough to submerge the whole tank. Soak at room temp for a week. Results= paint will fall off and no rust will be found. IF your tank has rusted thin or there is "bubbled rust" then the soak will eat it thru. If so, the tank was junk to start with.

So if you have varnish and rust. Do varnish removal then rust removal. I have done this many times and have guided others as well. It works.

CAUTION: Wear disposable gloves and safety glasses whenever using chemicals, rinse skin if splashed and wash clothes that have been contaminated-seperately. To neutralize the phosphoric acid use baking soda solution, to neutrialize Chrome cleaner, flush with water. The solutions you make can be filtered thru coffee filters and stored in plastic LABELED bottles and used several times over. Take any solutions that are dirty and dispose of them in a safe manner. You can neutralize phosphoric acid with baking soda in small quantities as it will foam. Once the foam subsides just flush down the drain. You can do the same with the chrome cleaner as the amount you are using is small and quite dilute.

[aaron7]

Even though the tank I have -looks- good I might still do this to make sure it's totally clean inside.

[Spokes]

If you have a freshly painted tank, and you have not had any trouble with dirt or rust plugging up the fuel bowl or carb, you might want to let it alone for now.

This tank cleaning technique is usually done when there is loose rust or "crud" in the tank, or a part of a restoration. I am in the market to buy a used tank and when I find it, I will take some pics and refresh the procedure. On monday, tommorrow, I am off to a Honda motorcycle junkyard, so I might have a tank soon to do.

[Spokes]

I found a great 1966 CA95 Gas Tank complete (of course without badges)
I plan do a visual cleaning and derusting procedure on this tank with before and after shots. The procedure will also address removing the original gas petcock, doing a rebuild on it, cleaning and polishing the original cap and replacing its gasket.

Should be cool for all to see.

[Spokes]

Well, I got the tank I bought off of eBay. "Nice tank" "Not rusted thru" No dents, just needs a good cleaning! Buying things off of eBay reminds me of bad blind dates in high school.

This is what the tank fuel petcock valve looked like when it arrived


Oh boy......Well here we go again. Soak the top with some chrome cleaner


After removing the screws, saving one and extracting 2 this is what it looked like


Bad news. The dreaded calcium. On the other side a broken bowl. After cleaning and removing the broken bowl threads, piece by piece.



I don't know if I can save it with all of the damage. The only salvagable part at this point is the valve selector handle, still has the plastic grip and looks like it may have been made from stainless steel.

Again, I preach about calcium in valves & tanks, a sure sign of standing water and a sure sign of trouble as the calcium holds moisture.

Alas, the tank has pinhole leaks. When I have removed all of the calcium (rust was easily removed within hours) I am going to do some research about repairing tanks. The tank is nice, the chrome panels are perfect. It's like that blind date....."Powder and paint make what you ain't" My mothers advice about dating........

[JasonandMichell]

This is awesome. Just what I'm looking for. I picked up my 1969 CA160 today and the inside of the tank is in great shape except for a couple rust bumps on the outside edges/bottoms (can't describe it). I need to do use one of these methods.

Question, though. Let's say I clean the tank of rust, then empty it and don't fill it for a year. Will I need to perform this task again at that point?

[Spokes]

If you have a few rust bumps perhaps just use BB's from your local Walmart sports dept. Fill the tank with one pack of BB's (holes plugged) and shake, rattle & roll for a few minutes to break the rust bubbles. Use the warm chrome cleaner solution to clean it out. Let the cleaner work for a few minutes and rinse well. While the tank is wet inside, spray well with WD40 to chase as much moisture out and allow to dry. Note: If you want to protect the paint on the outside of the tank, coat the outside with a light coating of chassis grease. When your finished rinse the grease off with WD40 and then with soap & water.

If the tank is going to sit without fuel for a while, just hit it again with WD40 or the like.

[JasonandMichell]

Ok, so this weekend (maybe tonight?) I plan on ridding my tank of rust. I bought some Meguiar's Chrome Cleaner and BBs.

Here's my question: once I shake, rattle, and roll the BBs and dump any pieces of rust that will have broken loose, A) How do y'all typically plug any and all holes? B) what is the water to Meguiars cleaner ratio you would use? EDIT: NEVER MIND. I misread the instructions. FILL THE TANK, then put in 1-2 pints.

I still haven't found a way to plug my tank other than maybe duct tape.

[Spokes]

I would use fuel tubing on the ports under the front of the tank. Put a bolt in the other end of the tubing and clamp. The bottom of the tank can be sealed by making a small plastic disc, cut from a food container (your gasket). Poke 3 holes for the petcock screws. Then cut a thin piece of wood in the same shape with 3 holes to match and bolt the plastic/wood "patch" to the bottom of the petcock opening.

[JasonandMichell]

Ok, Spokes, here's the deal. I learned two things about my tank while doing the "rust treatment". Again, mind the Blackberry pictures. My wife and I are trying to figure out how to cashflow replacing our busted one.

1) What's missing in the first picture?

2) There's a pinhole leak in the rear of the tank. Any ideas on how to patch it? I've never done anything like that, so I'm up for any ideas.

I will say, however, that Meguiar's Chrome Cleaner and some hot water worked wonders. The BB's destroyed the only rust bubble I could find, then MCC did the rest.

I know now why the previous owner wasn't using the petcock.

[Spokes]

What's missing is the petcock assembly. The pics show that the tank is in bad shape.The sealant around the rear mounts, the screw in the bottom of the tank, the newly found pin holes and of course the patched petcock opening.

Don't be too discouraged as finding an old gas tank that has been repaired over the years is pretty common.

Your choices are:
1.)Source a 1964-1966 CA95 tank or a 1966-1969 CA160 tank off of ebay.
Make sure that the tank offered has the 4 mounting posts. Somewhere around 1965 the CA95 tanks went to 4 post mounting, some 1965 & earlier have 2 posts and two front "C" mounts. These tanks you can't use unless you modify them as I did (you can see the pics in my album "Building a Honda CA95 from scratch)
2.) You can try some tank coating products that will seal the leaks. I hope some members who read this response chime in to let us know how the sealant works. The sealant may work well as long as the tank is clean and dry. http://cgi.ebay.com/ebaymotors/Gas-T...Q5fAccessories

If you go the sealant route, you will have to use the same tube feed as the previous owner....

I would source a good tank...$65-$120.00 ebay.

[JasonandMichell]

Thanks for all the info. I checked ebay, and there doesn't seem to be anything up for sale right now, although I'll keep my eye on it.

I have a co-worker that mentioned he has done some motorcycle tank welding in the past, so I might have him try to chase the leak. What are your thoughts on this?

At the end of the day, if I have to route the fuel through the front two "spouts", I guess it won't kill me. I'd like it to be original, but free is good, too.

Thanks again for the help, guys. I might try the Kreem sometime, too.

[Smithers]

Hmmm I have a spare tank that is in decent form but I haven't tested it for leaks. It needs to be rinsed clean. It has the four posts configuration but is missing one of them as they are barely tack welded on.

I just wouldn't put faith in any sealer. A friend of mine in the 4wd restoration business tried some sealer on a tank in one of his Jeeps and the sealer failed after a couple weeks and it completely gummed up his fuel system! So I run when I see that stuff on the shelves. Welding motorcycle tanks is easy with the steel in the old Honda tanks. Anyone should be able to weld up any leak in one of these for beer money.

About rust I've seen people use some pretty nasty tanks. They just put one or two of those clear fuel filters in the fuel line and that has been good enough for them.

[JasonandMichell]

Fair enough. The Meguiars cleared up most of the rust on the interior at least that I could see. I might still put an inline fuel filter.

My coworker also mentioned that he was thinking about welding the four mounts in place. Does anyone see any issue with that? I don't, other than making sure it's a clean weld.

[Smithers]

Those mounts are just waiting to fall off. Weld those suckers up nice and clean. It will give him good practice moving around in a circle too. :-)