Gas tank repair

[bgiller@xxxxxxxxx (Bruce Giller)]

	Got an early model Spider gas tank on order from IAP to replace the
GTVs sieve model.  The tank was supposed to arrive at the end of July but
has been delayed by a month and I've got reservations at Summit Point on
the 11th.  So I had to fix the leaky GTV tank.

	I had drained it out (by drilling a hole in the bottom) about 2
weeks before so the tank was dry.  Removed it from the car (getting really
good at this) and rinsed out the insides with water; a bit of rusty colored
water came out.  I had intended to fill a plastic concrete mixing tub with
water to check for leaks but the gas tank was too deep.  On to Plan B; I
plugged all the outlets in the tank except for one - this was to be used to
pressurized the tank.  Set the compressor to around 20psi, used a blo-gun
to pump up the tank until the sides 'cracked' mildly with the expansion.
Got some dishwashing soap (liquid kind), and bit of water and an old paint
brush.  With the tank under pressure, I painted the bottom of the tank with
soapy water and watched for bubbles to appear and marked all the holes with
a grease pencil.  Dried off the outside of the tank, sanded down the metal
around the holes until it was shiny ( sometimes I made more holes this
way), applied some solder flux (typical plumbers flux), heated up the area
with a propane torch and melted plumbers solder on it.  Took about 1 hour
or so to do it all.

	Filled the tank with water and left it over night (as if I was
worried about rust forming !) to see if it leaked under a normal load of
gas.  No leaks, and the tank is back in the car.  But I'm sure that rust is
still flaking off the bottom and being sucked into the filter.  I hope that
the new tank shows up soon.

	Most people worry about being blown up when having an open flame
next to a gas tank.  If you can't wait for a couple of weeks for the tank
to dry out, I heard about another technique that will work.  It is to hook
up a hose from the exhaust of a car (that runs) and tape the other end of
the hose to the filler neck of the gas tank.  Start the car and the exhaust
gas will fill the gas tank.  What you are doing is displacing the oxygen
with C02 (and other gases) to prevent an explosion.  You can now proceed
with soldering the tank.

	I think that the reason most shops don't weld new metal to the tank
is because by the time you need this to be done, there isn't any decent
metal in the tank to weld the new metal to.  That is why everyone
recommends lining the tank with a liquid sealer.  I was quoted a price of
$200 to have this done - my new tank costs a smidgen less than this.

"Is dis a system???"  Mr. Natural

Bruce Giller
Takoma 'Radiation-Free-Zone and Finally ReUnited' Park, Md
'73 Alfa GTV 2000
'86 Alfa Spider
'72 Moto Guzzi Eldorado

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