fuel tank cleaner

[jagnut66]

Hi,
My fuel tank has been sat in place but empty for a few years now, whilst I've been restoring Sally my series 2, I am now contemplating putting fuel in but, needless to say, I checked inside and found that the tank has become damp and rusty (surface) inside.
I should have expected that but 'c'est la vie................
Anyway, I was hoping that people on here would be able to recommend a good way to clean it out / a good fuel tank cleaner.
I did have the openings (filler neck and sender hole) blocked to stop debris getting in, the filler neck and cap are now refitted and I have left the sender hole open to air and hopefully dry it out somewhat.
I have a larger capacity flat topped 6.6ltr tank fitted with a drain.
Many thanks in advance for any help given.
Best wishes,
Mike.

[svenedin]

Whether it is worthwhile going to the trouble of cleaning it out properly all depends on whether it leaks or not. If it leaks it will need professional repair. First you need to degrease it with a strong detergent so that a chemical de-ruster can contact the metal surface without an oil barrier in the way. You can add some nuts and bolts and shake it all around. Then a chemical de-ruster such as phosphoric acid or citric acid. Bilt Hamber Deox C for instance. The citric acid type e.g Bilt Hamber works best hot or otherwise it can take days. When de-rusted it needs to be rinsed, dried and a sealant used quickly or it will flash rust.

Stephen

[philipkearney]

In addition to using a specialist rust treatment such as Bilt Hamber, having an 'agitator' in the tank to loosen rust and debris would be useful. Something such as a handful of nuts or bolts inside the tank, sealing the holes and then shaking vigorously to help de-scale the inside. At the NEC show last year, one club (I forget which one) demonstrated their homemade tank cleaner. This involved filling the tank with cleaning and nuts/bolts and then strapping it to a bike wheel which was powered by an electric motor and leaving it for a few hours. This saves a whole of tank shaking by hand !

[svenedin]

Interesting idea and similar to the tumblers that are used in industry to clean up cast metal parts. Those tumbling drums have ceramic beads in them.

You might as well use some old nuts and bolts that you actually want to keep because they will get de-rusted very nicely at the same time!

Stephen

[michael4]

In the days of Austin 7 ownership learned folk were know to put clean gravel or nuts and bolts in the tank and put it in a concrete mixer for a while. Noisy but it worked.

[Bill_qaz]

Be careful if you use an internal tank sealer after cleaning many react with ethanol in fuel. Lots of old bikes had issues as sealing of tanks was quite common.
Ratchet strapping the tank to a home cement mixer is good for the agitation. When you put old nuts and bolts in use a variety and some ball bearing if possible to get into the corners.
Diesel is good for the final flush and helps prevent flash rust if you decide not to internally seal the tank.

[Myrtles Man]

You could try rust removal by electrolysis like this:- https://www.youtube.com/watch?v=ICW01HFbaxc. It does work - I used the technique a while ago on a petrol tank.

[svenedin]

Be careful if you use an internal tank sealer after cleaning many react with ethanol in fuel. Lots of old bikes had issues as sealing of tanks was quite common.
Ratchet strapping the tank to a home cement mixer is good for the agitation. When you put old nuts and bolts in use a variety and some ball bearing if possible to get into the corners.
Diesel is good for the final flush and helps prevent flash rust if you decide not to internally seal the tank.

Yes. Probably a good idea to use some kind of epoxy sealant that sets once and then is impervious to solvents. I had a brand new fuel tank some years ago that shed particles of red paint into the fuel for quite some time.

Stephen

[Classiccars]

I was advised there are three components to selling a tank and it all adds up.

[jagnut66]

Whether it is worthwhile going to the trouble of cleaning it out properly all depends on whether it leaks or not.

This was a brand new tank when fitted a couple of years ago. Not a guarantee these days, I know, however I'd like to think there's at least a chance it won't leak when filled......
Lots of good advice / suggestions. I note the point about possible sealant reaction to our modern ethanol rich fuels.
Another question that occurs to me and which I should have included in my original post, is, given that this was a new tank and this should just be surface rust caused by dampness: Is there any chance I'll be okay to just continue to dry it out and when dry fill it up with fuel?
Or is this just wishful thinking?.....
Best wishes,
Mike.

[Bill_qaz]

If its just flash rust from dampness I would remove the tank and put a gallon of diesel in, move the tank around to get contact on all surfaces ,then empty it and fill with petrol. You shouldn't need any aggressive cleaning agent or procedure in light of your description. In my opinion

[svenedin]

I didn't realise that it was actually a new tank just a few years ago. I too would not go to great lengths to clean it up.

Stephen