I am moving my fuel pump and drained the tank for the hose hook up etc. I looked deep inside and noticed a little residue on the bottom. I am going to pull the screen too, might be more there.
Is there something to use to flush the tank that is not fuel?
This will be with the tank in place. I am NOT taking it out. Scope creep is killing me and I am already missing the best part of the driving season.

I get wanting to avoid scope creep, but have you changed the fuel lines under the tank recently? If not, now would be a good time to do so, and pulling it out of the car isn't that hard to do and would allow you to more easily clean it out.

They are fresh and I am changing some during this process, need longer in a case or two.

I would not use any water (or water-base). Any solvent would work--maybe ethanol?

I'd chose something that evaporates easily.

Acetone followed by alcohol maybe.

You will need big airflow and NO sparky!

Actually, thinking about it, AC flush would probably work fine.

It's a bit on the expensive side.

I sometimes use liquid B12 before the AC flush on a seriously poisoned AC system.

On a really bad one I'll use B12, then AC flush, then a shitload of alcohol.

Each fluid is better than the others on specific trash.

In place…
Laquer thinner, a good blast of air after it evaporates.
New screen, new, additional, racing filter that uses a stone so you can remove the filter and clean it with carb cleaner…
Place new filter between outlet and fuel pump.

Remove tank next winter.

Rich

Maybe a bit crude, but I have wrapped a paper towel around a stick and pulled tons of crap from the bottom of fuel tanks. Keep things a bit damp with fuel and you will be surprised what you can get. All done with the tank in place

"Mopping" it up will be needed with any solvent.

I keep what I call "dog towels" in the shop and sometimes they are sacrificial dog towels.

Old nasty, garage sale, disposable trash towels.

I keep a "dog towel" beach towel on the ground at all times.

If it's water/coolant it gets placed under the drain pans to catch what misses.

Once it gets NASTY, I pressure wash it and lay it on my driveway to dry.

I've been able to re-use it for 9 years now...

If they hit fuel or oil they end up in the trash.

I like this simple approach. I bet a couple of (painter's) tack clothes would be even better

.

I’ve used heavy duty oven cleaner with good results.
Apply-wait-rinse-repeat
Replace the strainer

It would seen to me that you can get a new tank for $227. All in no tax no shipping.

The cost of solvent is several $, Not a big deal to install the tank on no fire risk and no solvent to breath. You can sell the old tank for a few $ later

Best Bob B
Click to view attachment

I bought one from "parts geek" for my 75 BEFORE I even looked at the one I have.

Was about 250 all in...

Stupid cheap IMO.

If you tank is nice inside and just needs a little cleaning, I'd try what I suggested.

Lacquer thinner might be kick ass as well.

I've used oven cleaner extensively in cleaning up cast iron engine blocks.

That can CREATE corrosion so be really careful if you try it.

If you get it into the air, it will give you tiny little chemical burns for every microscopic drop that hits you.

MONSTER PPE for caustic cleaners and then MONSTER rinse out with first a low flow garden hose and then a pressure washer...

I believe the tank should come out for oven cleaner.

Now, oven cleaner works better than ANYTHING else for cleaning ferrous metals.
It DESTROYS alloys so NO overspray on anything alloy.

This is a tiny amount of foreign substance at the bottom, the tank is great, no need to pull it or replace it. I probably don't have to do anything but i am. I will replace the screen since it is drained already. I already have scope creep on this item and too many other items to list. But yes I do have a list. The list grows but the progress does not.

I used a battery charger and washing soda. Took 2 days and three rinses but it was perfect when I was done. I have a post someplace about it.

Agreed, the tank should come out whatever concoction is used.
Oven cleaner will stain and remove anodizing from aluminum so use caution

@rick 918-S

Inquiring minds want to know...

That sounds "non-destructive" as anything else and much safer to work with.

I would like to add that process to my mental tool box.

I'd really appreciate a link to your thread if you have time.

I can probably find it on my own if you don't.

Seldom do I see stuff that is NEW to me.

That may be "the ticket" for other things as well.

Thanks
Rick

If Lacquer thinner is used as suggested, I'd be sure to change the hoses after-wards (but that's more project creep). Also, I don't imagen oven cleaner to be liquid enough.. it foams up, right? I guess eventually it turns liquid and would drain out. Remember though, the OP has stated the tank is not that bad and will stay in the car. Again, I'd do tack rags on a stick, rinse with small amounts of gas - repeat til clean. If hose will be changed out, maybe use acetone to rinse, since it's cheaper that lacquer thinner. JMHO

I will dig up the photos and or the post I did. I used the process on the tank for 7 of 9.

Found it on Page 6

http://www.914world.com/bbs2/index.php?sho...4128&st=100 I had to grind the rust off the Rod in the tank about every 4 hours or so the first day. Then I changed the water/soda solution at about 4 hours then new solution the next day. You have to be sure to keep the positive electrode from grounding out on the tank. U wrapped tape around the electrode where it passed through the tank opening.

Removing the tank is one fastener on the strap & disconnecting the fuel lines (that are being or should be replaced if they have any age at all on them). IIRC replacing the in-tank screen/"sock" isn't easy with the tank still in, but I'm not sure.

If it's loose dirt or crud that you're trying to clean out, how could you get it out with the reserve tank/reservoir at the bottom of the tank? (Mabe using the above "mop" method)

Take it outside and spray some carb celaner in there, maybe let it soak awhile, then rinse out with some fuel.

I flipped the tank over on a set of saw horses and used the garden hose to flush it. I] also have a pressure washer that has a little more force. Then turn the tank on the side where there is a large gap between the baffle and the tank and continue to rinse. Repeat the washing soda process until you are confident you have it clean. Then dump in Marvel Mystery Oil or W-D 40 or something similar to preserve the tank until you start to use it.

I just wanted to add that the expansion tank needs to be removed BEFORE the tank comes out of it's mounted location. The reason is because the electrical plug is installed under it, and can not be disconnected until the expansion tank is removed.

I recently forgot this fact when pulling the tank for my M/C install. My wiring harness was missing the actual electrical plug to the level sender when I got the car... and I'd always wondered how that happened. I spliced in a replacement though, and installed the tank etc. Then several weeks later while having to remove the tank again for the M/C install - I forgot to remove the expansion tank, and disconnect the electrical plug and ended up ripping my wiring splice(s), so I got to do that over again

Our 73 911 sat for years after we had Jim Newton repaint it in 1988. The tank crudded up from sitting with old gas. The first go at it in 2000 was to pull the screen and clean it with brakekleen and we were able to drive it from New Jersey to Vermont and a few trips around the Valley. Then it spent the next 15 years in the garage except to pull it out, wash it, Sue would say let’s take it for a ride. Then no, what happens if we get a stone chip and back it goes into the garage for another year. We finally decided to sell in 2017 and the car would always quit, run rough, stall, etc. Replaced the fuel lines and tank screen fitting and flushed the tank with Muriatic acid. Worked great for a year then it started doing the same thing. Replaced the tank with a new one and problem solved. If your car is going to sit like ours did, fill the tank with 100LL avgas. Airplanes sit and a gas does not sour like auto gas does. Don’t run a gas in a car with cats as it has lead.

Good luck as this was a loooong road!

Charlie

One of my customer cars, a 1970 Chevelle SS currently has 10+ year old 100LL in it.
Works FINE!
Same guy ran 100LL in his lawn equipment. At the 5 year point they started misfiring.
Tank perfect!
Carb perfect!
Plug, badly lead fouled!
Clean plug.
Good for another 5?

I have used muriatic acid as well with same results.

I REALLY like rick 918-S suggestions and will try that the next time I need to clean a nasty tank out.