Gas Tank Leak

[clayfoushee]

Found a little pool of gas under my car this afternoon. I've always had a faint whiff of gas when I opened the trunk and assumed it was from the vent.

Pulled the carpet back, and there is gas pooling in the back corner, driver's side in the tray beside the tank. Dried it out and returned a half hour later, only to find more. The fittings appear tight (both vent and pickup). It's not at the filler neck or filler hose entry to the tank. It's not at the top on the sending unit either.

Anyone have an actual tank develop a leak?

Clay

'98 Unique #9299, 427FE side oiler, top-loader (close), 3.31 rear

Annapolis, MD

[Poorboy]

Clay,
A few have had the fitting at the bottom leak. The only way to be sure would be plug the filler neck, gas line & vent then put a little pressure on the tank. I would apply the pressure though the filler neck.

Poorboy

PS, All you need is a few pounds of pressure(3-4)

[Unique 289_FIA]

Just tackled that exact same problem last weekend. Emptied the gas, pulled the tank and filled it with water. Watch for leaks around the welds. I found a tiny crack in one of the bottom welds on the passenger side. Empty and dry thoroughly (hint: if you have a 2 1/2" hose Shop Vac, slip it over the intake. Take off the fuel pressure sender cap and turn the vac on in blower mode. Check inside with flashlight until dry.) I used some of the fuel tank repair epoxy you can find at any auto parts store. So far, so good!

I also drilled a small hole in the driver side rear of the tank tray for draining, the gas seems to collect that direction.

Good luck!


Unique Motorcars 289 F.I.A. # 9142
Southern Automotive 354 stroker

[clayfoushee]

Poorboy and FIA,

Yep, that's where it's collecting. I spoke to Lee Dahmer, and he said the tray was slanted in that direction, so it's probably at the pickup fitting.

I just filled up the tank yesterday and it was in the mid-90's so it's probably worse under pressure of a full tank with the gas expanding.

Clay

'98 Unique #9299, 427FE side oiler, top-loader (close), 3.31 rear

Annapolis, MD

[Unique 289_FIA]

Clay,

That's where mine seemed to leak also, but it turned out to not be the fitting, but a crack in the weld on the passenger side. If it leaked from the fitting, I would think it would drip to the ground rather than the tray. One way to find out is to drill a small (1/8") hole in the driver's side rear corner of the tray. If it was like mine, the gas is collecting there until the level gets high enough to overflow to the back hole by the fitting. If it comes streaming out of the hole, I'd pull the tank and check it.

Unique Motorcars 289 F.I.A. # 9142
Southern Automotive 354 stroker

[clayfoushee]

FIA, you're right, either way I'm going to have to pull the tank. I don't have a hole drilled in the tray, so it is leaking through the driver's side holes drilled in the tray for the the tank pickup and vent fittings. I've got paper towels in there now to soak it up, and it doesn't leak until enough collects.

Clay

'98 Unique #9299, 427FE side oiler, top-loader (close), 3.31 rear

Annapolis, MD

[bittentoo]

STOP!!!! A word to the wise. DO NOT pressure test your gas tank with air! The atmosphere within the tank is oxygen starved due to the gas vapors which makes everything safe. But when you introduce compressed air to raise the pressure within the tank, you have completed two of the three needed components of the fuel triangle. Fuel, air and pressure relates to heat (ignition source)! If you must pressurize a gas tank, rent a bottle of nitrogen fron the welding supply and do it safely.

Please. I don't want to go to a funeral for one of my cobra buds.

Kelly

[clayfoushee]

Thanks Kelly my friend. I'm just going to drain it, pull it and figure out the source of the leak with it out of the car. You're quite right.....gas vapors are not to be fooled with!!!!!!!!!!!

It ain't the liquid that ignites...it's the vapors that will kill you. We had an interesting little demo when I was at FAA a few years back where we purposely crashed an entire 707 trying to test a new type of less-explosive fuel....:D The explosion was spectacular.

Clay

'98 Unique #9299, 427FE side oiler, top-loader (close), 3.31 rear

Annapolis, MD

[brfutbrian]

just pull the tank and have a radiator shop that repairs aluminum radiators fix it. as long as you dont tell them its from your cobra replica it shouldnt cost too much. i find when you say the words "cobra replica" the price tends to jump. brian.

[clayfoushee]

Thanks Brian, as well as for the quote earlier today...."don't argue with fools, so you don't start looking like one." Made me think as I was having my head handed to me over on CC.

Clay

'98 Unique #9299, 427FE side oiler, top-loader (close), 3.31 rear

Annapolis, MD

[homer]

I had a leak in the main pick up fitting that was very slight. Turned out that the hole to receive the fitting had been tapped too deep and the fitting would not seal regardless of the amount of teflon tape. Unique was terrific -- I sent them a digital picture of the problem and sent the tank back to be repaired, no questions asked

[clayfoushee]

Turns out Homer was right. The leak was very slight at the main pick up fitting. Used a Permatex sealing product recommended by Lee Dahmer. The seams all look fine. It's about half full of gas now and not leaking.

Clay

'98 Unique #9299, 427FE side oiler, top-loader (close), 3.31 rear

Annapolis, MD

[gasman]

Glad it worked out so easily.

Steve Foushee
Unique #4279389