leaking fuel tank

[kartone]

Just found a pin-hole leak located on the bottom of the fuel tank of my 1980 GTV. I intend to remove the tank and inspect it, what is the best way to inspect for corrosion ? 

[Cool Jesus]

Try these links, I'll be doing some preventative cleaning for my rebuild too; I haven't researched the links too deeply as far as plugging holes. I'd imagine a treatment may be thick enough to seal pin holes, however after cleaning they may get bigger and require more substantial plugging such as welding/brassing?

http://www.mopedarmy.com/wiki/Removing_rust_from_a_gas_tank
http://www.alfaclubvic.org.au/forum/index.php?topic=8292.0
http://www.alfabb.com/bb/forums/carburetors-fuel-injection/25088-corrosion-my-gtv-tank.html

[colcol]

I usually solder pin holes in petrol tanks, use soft solder and a big soldering iron, don't use flame for obvious reason, and you don't want too much heat, because you will distort it and remove any anti rust plating there, remove any corrosion caused by the flux and paint the bare metal on the outside to avoid rust, Colin.

[aggie57]

If you want to do things carefully, fill the tank with water to purge the fuel vapors before repairing it.

[MD]

I agree with aggie57.

To get any traces of water out after the job is done and it has totally cooled down, slosh a couple of litre of methylated spirits around in the tank and then empty this fluid.

The metho will mix with any water residue and be removed with it.

The second benefit of this procedure is a confirmation that the leak has been fixed (or not)prior to installation.

[kartone]

Guys, thanks for the input. I will be pulling the tank off tonight, will let you know what I find (if interesting will post photos), hopefully I can solve the problem with an epoxy liner.

[Cool Jesus]

Was speaking to a workmate today whom I today discovered was a closet Alfisti in his younger days. He mentioned out of the blue that these fuel tanks had a common problem of hairline stress fractures on the bottom. This was due to the way the reinforcment ribbing was pressed into the sheet matel, accompanied with the large size of the tank bottom and the weight of the fuel would bounce about flexing the sheet metal and then causing these stress fractures along the line of the ribbing. Could this be what Al's looking at?

[kartone]

Cool Jesus, spot on ! The pinhole is located on the ridge of a reinforcement rib pressed into the sheet metal on the bottom of the tank. As you stated the area is quite broad and flat therefore subject to flexing under the load of the fuel.

[colcol]

Years ago i had endless trouble with a steel fuel tank, leaking and rusting and clogging the fuel lines and carbs, car would run stop, because all the flakes of rust would clog the pickup, the after about half an hour the rust flakes would fall off the pickup and my car would run, for a while, then i got smart and fitted a plastic fuel tank, no more problems ever, finished, should have done it years ago, plastic fuel tanks came in in the early 80's, could you get one for an Alfetta?, Colin.

[Cool Jesus]

Kartone, sorry mate, I called you Al, had my head in another post. Well fcuk me, I got one right then  I can't remember if any fix for it was mentioned, I'll ask him tomorrow. Logic would dictate some reinforcement ribs on the bottom to lessen the flexing.

I usually solder pin holes in petrol tanks, use soft solder and a big soldering iron

I was apprehensive at suggesting this, perhaps I should have posed the question. Have you had success with soldering Col? Is it strong enough to deal with any pressure build up or do these tanks have enough venting to negate this occuring? I suggested brazing as I thought this would have more resistance, although plumbers solder water and gas pipes. Soldering would certainly be easier.

[aggie57]

I was apprehensive at suggesting this, perhaps I should have posed the question. Have you had success with soldering Col? Is it strong enough to deal with any pressure build up or do these tanks have enough venting to negate this occuring? I suggested brazing as I thought this would have more resistance, although plumbers solder water and gas pipes. Soldering would certainly be easier.

I had a solder repair done on my 1973 GTV in Temora NSW while on a road trip back in 1983.  Now granted the car only drove  for another couple of years but the repaid is still there.  Hope it still holds!

[kartone]

Besides the pinhole on the reinforcement rib (see photo) the tank is in excellent condition. Should I use the epoxy or solder ?

[Cool Jesus]

From what experience Col and aggie have had it sounds like solder is the way to go. My work colleage had his tank repaired at a radiator shop, where they formed a brass sheet to cover the entire bottom and shaped to the ribbing. It was then soldered in place. This reinforced the tank from flexing and repaired the fractures at the same time. Don't know if you need to go to this extreme considering what the others have said. Instead of an entire covering, I'm sure a radiator shop could just patch it up relatively cheap. I'd imagine an entire fix as suggested by my mate would be costly? Where as a simple brassing or soldering would be more than $50 at a guess. Alternatively price a second hand unit against the fix, there's a few forum members breaking Alfettas.

[colcol]

The soft solder i used on the tank held for years..., until i wised up when i found out about plastic tanks, you could braze it, but you risk distorting tank and removing any plating on the inside of the tank, plus you will have to fill the entire tank with water, if you want to introduce flame, you need a big soldering iron to get enough heat into it, but once you do and the flux starts to bubble and the soft solder melts, you are in business, i stuffed about with this problem for 15 years, with the car constantly breaking down, due to a rusty tank, strangely, i have had no such trouble with the metal tank in the 33, but then i have only owned it for 26 years...., Colin.

[GTVeloce]

Not wanting to take advantage of a situation...but I have a perfectly good tank that has just come out of an 83 GTV for sale if you wanted to replace in stead of repair.