fuel tank leak

[rwarre]

Having trouble finding the leak in my right fuel tank. Used the manometer method and the balloon. Have tape over the gas cap. I have sprayed the tank with soapy water, used a brush to brush on the soluton, and tried to listen/feel where air might be escaping. No luck. Has anyone pressurized the tank and set it in water, like a bathtub. Tires are done this way. My soap solution is 7 to 1 recommended by a plummer. When I use the manometer method, the water level starts going down immediately very slowly.

[Pirkka]

Originally Posted by rwarre

Having trouble finding the leak in my right fuel tank. Used the manometer method and the balloon. Have tape over the gas cap. I have sprayed the tank with soapy water, used a brush to brush on the soluton, and tried to listen/feel where air might be escaping. No luck. Has anyone pressurized the tank and set it in water, like a bathtub. Tires are done this way. My soap solution is 7 to 1 recommended by a plummer. When I use the manometer method, the water level starts going down immediately very slowly.

Manometer and it's connections/connectors are leak-proof? Trying to put tank in to water sound like too complicated. Soapy water should do just fine -- try once more? Get friend to look with you -- you are already too tired to look carefully enough. From Van'sairforce.net you can look for another threads where the obvious leaks are but I think to save time just go and test your tank more: connectors especially.

[Pilottonny]

I tested the tanks with 10 liters of fuel, worked fine. When you close the cap, the fuel will pressurise itself, any leaks show-up immediately. Just turn the tank around and leave it in each position for a few minutes, so that the gas has reached all the internal surfaces of the tank.

Always be carefull with gas, though!

Regards, Tonny.

[tinman]

Add some ultraviolet tracer dye in the fuel when testing. Sometimes the leak isn't really a leak...more like a weep. The dye will leave a trace behind after the fuel evaporates. The local auto parts store should have it for around $8 per bottle.

[N941WR]

Have you put fuel lube on the fuel cap O-ring? They tend to leak in the test.

I would put fuel in the tank as a last resort as you will have to clean it out to fix the leak.

[RV7Builder]

I took my tank out to our pond, tossed it in and sat on top of it. I still had the manometer hooked up with water in it. I was able to maintain a slightly positive pressure by manipulating the tube. The leak I couldn't find with soapy water showed up immediately. It was in my manometer connections...

[Jeff R]

As Bill said, check the fuel cap. I had a really small leak there that was hard to see with the soapy water.

[Aden Rich]

The submersion in water is best. Your local tire dealer should have tank filled with water to check for leaks. You could take it there or like the one guy said, throw it in a pond and lay on it. I had a leak up in the very top outboard corner that took forever to find. It would only leak when the tank was totally full and in the taildragger mode. If I ran any level out of the tank it wouldn't show up.

[664781]

I put both my tanks in my pool to leak check via the ballon method. Found the caps leaking thru the center o-rings. Worked great!