Classic cars forum & vehicle restoration.

[Rick]

Evening all,

I had a peer inside the Velo's tank the other day, and it reminded me of something I need to attend to sometime.

It looks like a slosh-type sealant has been poured inside the tank. My guess is that this was circa 2000/2001. The bike was fired up a few times back then, and on a couple of occasions about 4 years ago in the garage. I noticed back then that the sealant stuff has broken up inside, falling off the inner surfaces of the tank, leaving crusty sheets/slivers of this yellow stuff throughout the tank.

Some I can pull out using my fingers, and a long picker tool, but only one side of the tank - beneath the filler - can be seen, and I assume the same sorry mess is also to be found over to the left side, out of sight.

Ultimately it'll all need to come out, has anyone a good suggestion on how to do it??

I had both fuel tanks on big Dodge restored, this required the tanks to be cut open, cleaned internally, then welded back up before ethanol-friendly sealant was applied. I'd prefer not to have the Velo's tank opened up, but is there any other way of getting all the crud out??

RJ
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[ka]

Mine has gone the same on the Morgan, other than filling with gravel and shaking, I could use some advice as well.
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KA

Better three than four.

[D4B]

I had this on one of my Peugeot van fuel tanks. I too tried sloshing some M8 nuts around but not much improvement.
I had to find a replacement. These broken up bits of old sealant were the cause of several fuel starvation break downs....





inside the old tank



compared to inside it's replacement

[MikeEdwards]

A chap I know swears by using molasses (a sugar by-product) for cleaning out the inside of petrol tanks, but that was mainly for removing rust rather than slosh tank sealant. Might work, though, and is relatively cheap to try out.

I think some of the early slosh tank sealers (and by early I mean up to about three years ago) weren't happy with increasing amounts of ethanol in petrol, but I assume this problem is just though it standing - I expected those that are not tolerant to melt off rather than to harden and crack. I am thinking of using some of this stuff in my project as replacement tanks are hard to come by (in any better state than the tanks I have) - looks like I might need to reconsider.

[bob2]

Molasses is something I have tried on my cousin's fiat 124 petrol tank. It was ok for a couple of years but last time we took it out for a run it began stalling again and we found the in line fuel filter which we have placed near the tank full of rust particles yet again. It was full and not letting petrol pass through!
I adviced him on putting some tank sealant in it but as yet he has not done anything yet!

[MikeEdwards]

I did mean use molasses to clean out the tank, not as a replacement for the sealant. I guess if it's getting damp (which may just be from the condensation off the petrol in the tank if it's left part full) it will just rust again.

[norustplease]

It sounds as if Rick's original problem is probably because the tank was 'sloshed' without having the rust removed properly and it has just carried on corroding and debonded the lining material.

Short of cutting out a section of the tank, probably the only way to remove all of the loose stuff is to use the gravel technique and periodically use an endoscope (which you can hire from a tool hire shop) to look inside and see how you are progressing. Molasses on the end product would be beneficial, but then it needs following up with one of the proprietary liner systems to kill any remaining surface rust and coat the tank. Rustbuster and Frosts both do reputable systems.
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1953 Citroen Traction
1964 Volvo PV544
1957 Austin A55 Mk 1
Boring Tucson SUV

[ukdave2002]

SPL would be able to sort it, but their normal process would remove all the outer paint and any soldered joints

If its the ethanol in fuel that this lining doesn't like, then at least you have a starting point for establishing what solvent would disolve the rest of the coating, if this is the case then some ethyl acetate thinners would make short work of it. See if some of the wifes nail varnish remover has any effect on on a sample, if it does then nip down to the paint supplier and get a gallon of thinners.

Re using Molasses, take a look here

Dave