Gas Tank

Ok, at 4$ + per gallon I can't ignore this any more. I have a gas tank that leaks when I turn to the right and it is more than half full. The filler
tube is my suspect since it is on that side. When I tackle this job I would only be too happy to find that the overflow tube or filler tube has a crack in it after 26 years of service. However I have to drop the tank out to inspect it and when I do I want to be ready for anything....short of buying a new tank in advance. My main concern is that the upper surface of the tank is hidden from view/inspection unless you remove it from the car. So once I have effected a repair on the leak I do not want take it apart again in the near future.
If I find some surface rust how should I procede? I know enough to fill the tank with water and leave it. But then what do you folks suggest as a way to seal it up.
I could sand off the surface rust and use fiberglass as an outer skin if really pretty pitted. A good priming with Rustoleum rusty metal primer is a thought if the rust is not so deep. I could follow that by a spray of some rustproofing type tar.
Unlikely because of how the leak presents itself but if I should find a hole or seam the is leaking what sort of "epoxy" do you find works best. Yes I do weld but I am a self taught stick only kind of guy. I'll repair your utility trailer but much under an eigth of an inch thick and I burn nice big holes in it. This plus the obvious explosion hazzards and my blood pressure would skyrocket so high I wouldn't be able to focus my eyes anyhow.
For the record the beloved car is a 1983 Mazda RX-7 so replacement parts are pretty tough to find...and expensive. It has a recess in it's upper surface that allows for the spare tire to be stored or I would consider a simple replacement tank.
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wrote:

http://www.tunerjunkyard.com
(Truth in Spamming Notice) My son's Ebay store. Can't say whether he's ever sold a fuel tank or not, but it might be worth asking. He has 2 1st generation RX-7 and looking at a third. One he's parting out for the store -- and his own Rex.
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wrote:

It is very likely that its the rubber overflow or return line thats cracked or leaking, or the rubber boot (if one) between the filler neck and the tank body.
Ive owned two trucks where both of those finally cracked and started leaking on turns or when filling up to full.
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The more I drive the tank empty it leaks less and only on a right hand turn...so the fuel is sloshing towards the driver's side which is the same side the filler is on. The access is terrible and I doubt I can take off the rubberboot (as you call it) without cutting it off. the overfill/vent tube is smaller and I will start there. If I cut the boot off I might get lucky and find the hole but still likely going to have to drop the tank to replace it.
Here is a thought to further pinpoint where it is leaking. If I were to remove the vent tube and simply wrap the boot with duct tape it should seal any leaks until the glue on the tape lets go. Perhaps a plastic baggy wrapped around the hose then duct tape to hold that firmly in place and a quick trip around the block. No leaks would mean in the sealed section of the hose...well wouldn't it???
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Instead of a plastic baggie, use rubber tape.
The additives in gasoline will eat the plastic just like it will the rubber filler hose.
I've got to replace both hoses to a gasoline tank on my FW RV: the $%^& gasohol additives ate them both up.
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The gasohol will also eat the rubber O-rings in your fuel injectors. At least it did in my Mazda RX-7.
73 Gary
wrote:

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{ SNIP!! }
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wrote:

Use either a hand mirror or a small digital camera right after making a series of sharp turns. Be sure to use macro mode
Frankly...I learned to never fill above 3/4 tank and left them both alone. Both were Ford Rangers
Im hoping the current Ranger doesnt develope this issue
Gunner
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"Gunner" wrote: Use either a hand mirror or a small digital camera right after making

^^^^^^^^^^^^^^^^^^^ You have a hand mirror with macro mode? Must be one of those concave ones.
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When both tanks in my '90 Ford half ton started leaking I took it to the dealer and he gave it a smoke test. No not with a candle. He had a machine that generated smoke (without flame) and fed it into the tanks under a little preasure. Turned out that the tank straps had worn through the tops of the tanks and they were leaking out of the top when nearly full and the truck was turned or braked. You could see the smoke coming out of the leaks quite easily. You might try to find a -safe- way to generate some smoke or just take it to a dealer shop that has a machine. Doesn't have to be a Mazda dealer. I had an '86 Mazda RX7 Turbo II, nice car as long as it ran. 73 Gary
wrote:

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An idea to ponder - attaching a CO2 horn with tape and dumping the tank into the gas tank. It should condense fumes, (would freeze moisture) and likely be plenty to smoke out a hole.
The bad news other than the ice, is it might crack any rubber hoses used to/from the tank that are exposed. [ so discard this idea ]
So I'd discard this way and maybe talk to the guys that smoke houses looking for air leaks. Insulation engineers.
Martin
Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net TSRA, Endowed; NRA LOH & Patron Member, Golden Eagle, Patriot's Medal. NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member. http://lufkinced.com /
Gary Pewitt wrote:

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There is also the possibility of deforming or rupturing the tank from the pressure. Some tanks have rather large flat areas that can't be too strong. I was going to suggest a small air pressure, such as from the pressure side of a vacuum cleaner, in the tank and soapy water in a sprayer. I thought it would be too hazardous, especially from the fumes.
Don Young
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