Gas tank leak

[larrybarone]

My 1984 fiat spider 124 has a pin hole leak/s in trunk. Not sur how to drain gas to repair it. Can i remove top half of tank without disconnecting lines and fuel pump.
Any suggestions are really appreciated. Just bought the car and was wire brushing rust from flat part of tank on trunk floor and sprung a leak.All store bought patch materials don't work with gas present.

[blurple124]

If you are going to weld in a new piece of metal to do a proper repair job, you will have to drain the tank of gasoline, and, ideally remove it from the car (not sure what you mean by "top half").
Once the tank is out, fill it with water (don't try welding an empty gas tank--gasoline fumes are flammable, not the liquid. Filling it with water vacates these fumes) then weld in your patch. Perhaps there are other tips that other members can give you, but that is the best solution in my mind.

If you are looking for a quick, easy fix, something like JB weld might do the trick. Not sure how the epoxy in it will deal with the gasoline, though.

That having been said, if you came across such a thin spot in an area you could access, who knows what may be hiding from you. Taking the tank out is probably worth the effort.

[leftfield6]

For my money, unless you are really savvy at welding and brazing, this is a job better done by a radiator repair shop. They are experienced in dealing with gas tanks, and have the tools and knowledge to do the job safely and correctly.

[azruss]

these tanks are not 2 piece. the earlier tanks had a drain plug. with your tank you can drain it in a couple of ways. both have hazards involved. First you could pull the gage sending unit. be VERY careful unscrewing those tiny nuts as you can twist off a stud. Then you would have to siphon the gas out. If you dont want to do it that way, you can disconnect the fuel hose under the car. be ready because gas will come roaring out of that hose. take a plug under there like a pencil or small cork in case you have to stop the flow. make sure you have a container big enough to hold what fuel you have. the siphon method is easier to control.

[124JOE]

yes jb weld says on it for gas tanks

i would put some black rtv silicone gasket maker on a stainless steel screw and drive it home

[larrybarone]

well i decided to pull the gas tank.First thing i did was disconnect all hoses from the top half of tank in the trunk.Then i removed the gas gauge float mechanism.Then i siphoned most of the gas out.I removed the nuts holding the top half of tank in place.Then came the problem with rusted nuts that i cannot loosen as they are rounded over from being so rusty.
Of course thay are the hardest ones to get to and see on the backside and sid of the tank.
Anyone have any trcks or ideas on how to get these off? Sure could use some help here.....

[boogiedude]

yes jb weld says on it for gas tanks

i would put some black rtv silicone gasket maker on a stainless steel screw and drive it home

Gas eats RTV real quick. JB weld should be good though

[azruss]

those rusted nuts on the back are tough. if you can find a long chisel, you might be able to carefully split the nut. chances are you will eff up the threads. If it were me, i would drill out the studs from under the car and replace them with bolts you can glue into place from the underside. Dont know if anyone sells those studs.

[larrybarone]

the tank looks like a two pc unit .Top half in the trunk with gasket and the bottom half under the car?How do you drill the studs without creating heat and sparks.

[124JOE]

no theres the top and bottom of tank seamed together then it sits ontop of the hole
and hangs down.i just had mine out
sears makes a set of nut removers they work great on a ratchet
if you snap a stud off you can drill it out

[DocGraphics]

Heres a pic of my tank out of car.
Tank is one piece & sets in from the top onto studs in the bottom of the trunk.
You can see the holes along the edge of the tank.

[jsab]

Dry ice will inert oxygen in a tank when mixed with water. Fill the tank half way and drop in some dry ice, then finish filling it. Use brass or bronze tools ( hammers, chisels, drill bits etc..) when working on a tank, they don't spark when struck.

[larrybarone]

well I finally got the tank out. I bought a stripped nut/bolt kit from sears made by master mechanic but it had plastic inserts that immediately broke. I bought an all metal socket set from Tools Plus in Waterbury,Ct made by Irwin and it worked great.
Thanks for the help ,all that posted replies.
I pulled all the hoses off even the ones with the crimped hose clamps.From the pisture i saw maybe I should have disconected from the other end?
How do i reconnect these hoses?
Also is it cheaper to buy a new tank or have this one fixed,has at least one hole and some rust in other areas.

[124JOE]

it dosent seem so bad
id get it fixed
use small hose clamps,put the bolt on the side not on the top
di you get new nuts?you can get stainless 10mm1.25 pitch

is your pan flat and straight?
mine was bent down in the ft side
i used a rubber hammer to make it straight
then when all was clean and painted i used a CLOSED CELL window foam
along the trunk and replced the tank
it has to go in swinging so watch the new gasket

wire brush your rust and paint with rustOlium
it will look so good