Sudden Tank Leak

[yankee-flyer]

Noon Saturday. I get a call from a hangar mate: "There's gas all over the floor under your plane!" Rush to the airport and sure enough there's a large pool of gas on the floor. Fuel is dripping off the bottom at about 1 drip every 6-10 seconds. Sight gauge has gone from 11 gallons to 10. Pull the bird out of the hangar, open the inspection plates and it's dripping off the bottom of the tank just above the line connections-- NOT from the lines. Pulled the carpets and they were not wet,-- no sign of leak around the sight glass. Got the tank drained and will pull it out Monday. Month-old paint is blistered along a couple of rows of rivets on the belly.
Tank was not leaking when last flown 18 Dec. Was not leaking when 5 gallons were added 21 December. Any idea why a tank would suddenly start leaking at a pretty good rate while it's just sitting there?

Wayne 120241/143WM

 

[rschy]

Were you naughty last year?

 

[thinkn9a]

did it get much warmer? cold gas outside,.. warm inside

bugs cold and needing somewhere to plug up and hide? (overpressure on the tank)

any better description on where the leak was.... any chance it is a old cork gasket that gave up the ghost?

other than that,.. must be the grinch,..

 

[thinkn9a]

OOPS,.. sorry,.. did not notice it was on a 12

will post again and bump it to top.... maybe someone else will have a useful thought...

 

[Frankpav]

Fuel tank leak

I experienced a fuel tank leak on my RV12 last July one day after I arrived in Petaluma, CA from Ohio. There was a wet spot on the floor and a wet spot on the fuselage at the right most access panel. It was tinted blue but there were no blue airsteams on the belly of the plane; which would indicate leakage while flying. The leak was at the lower, right, front corner and appeared to come from a rivet near the corner. I made two attempts over the next 5-6 days to epoxy the leak externally but was unsuccessful. Upon returning home, I ordered a new pre-built tank from Van's. When examining the original tank, I pressurized the tank and discovered that the leak would occur at the junction of the cross-tank support and the lower, right corner and the leak would increase if I twisted the support. The flight through Texas and Arizona was extremely rough during the afternoons. I subscribed that to the 110F ground temps and rising hot air. Those hours of turbulence might have precipitated my leak by stressing the tank. I'm grateful that the leak didn't occur in flight and when I was going over the mountains. I repaired the original tank by removing the sensor flange to gain access, cleaned the corner area and liberally applied more pro-seal and when cured, it held 0.2 psi for 72 hours. I now have a back-up tank. Frank