Fuel Tanks Leak! October 10th, 2009
Well, after a few days of the water level going up and down, it was pretty obvious that the level was decreasing, even after compensating for temperature. Not good. Appropriate swearing and grinding of teeth proceeded.
Using a spray bottle, I started applying soapy water to the tank, looking for bubbles….nothing….until the very end, when I sprayed the end rib with the inspection plate, fuel vent, etc. A little tiny bubble was forming right on the center pin of the BNC connector used for the capacitive fuel sensor! More swearing and grinding of teeth.
I was sure I used A LOT of Proseal on the inside of the BNC, but apparently I missed a tiny spot somewhere. This was a VERY small leak, but still a leak.
I wasn’t about to crack open the tank for this, so I figured I’d try a couple of things first. Vans suggests using some wicking Loctite (Loctite #290) for small leaks like this. Of course, Home Depot carries all kinds of Loctite except this one. I went to Grainger and ordered a small bottle for about $14. Meanwhile, I mixed up Proseal (the regular fuel tank sealant) and thinned it with MEK. Using a sowing needle, I put a drop of Proseal on the BNC center pin. Using some of the clear plastic hose connected to my compressor, I applied about 20psi to the outside of the connector, pushing the Proseal into the center pin leak. I did this a few times until no more Proseal would go in. I did this on both tanks, and left them to dry standing up on the outboard rib (i.e., so the BNC connector was vertical to the ground).
Once the Loctite arrived, I used a syringe to draw some of it from the bottle, and then placed a small drop of it on each center pin. I waited one day, and re-tested both tanks.
No Leaks!! …the water column held pressure for 4 days!