Like many others, my -7A developed a fuel odor upon opening the canopy. I traced it back to leaking flange gaskets on the fuel sensor, which I've attached a photo of. They look to be made of rubber and are about 1/8" thick.
They are the OEM gaskets installed in 2005 when I completed the plane. That's a pretty long service life of 16 years. Truth be told, I've had fuel streaking under each wing for the past 5 years or so that I attributed to leaking quick drains, but no fuel odor in the cabin until now. I searched the forums and found many suggestions to use "ProSeal", technically ChemSeal, instead of the gaskets.
I looked on vansaircraft website for the gaskets and couldn't find them right away and with uncertain shipping delivery times, I wasn't confident ordering from them with the time crunch I had. Since I'm much closer to Aircraft Spruce East, I ordered the ChemSeal 3.5 oz all in one tube. I defueled the plane, let it sit empty for a couple of days while I waited to receive the ChemSeal, mixed up the ChemSeal, replaced the #8 screws with #8 socket head screws as some suggested, placed a bead of sealant on the inside of the screws and the screws themselves, tightened them all down on both tanks, let them cure for 3 days (primarily because it was cooler than the recommended 77F degree curing temperature), fueled the plane back up yesterday, and, viola, no leaks. So, all told, about a 10 day downtime.
BUT, and this is the whole point of this post, was it really necessary to use ChemSeal? No, not with some fore knowledge and a little advance planning. The gaskets didn't leak for 7 to 10 years. Nothing lasts forever and if you consider the gaskets a life-limited item and just replace them every 5 to 7 years, you get the same, no leaks, result. The benefit is that the flanges were very easy to remove with just a stubby Phillips screwdriver. Should it be necessary to replace a defective fuel sensor, one could easily accomplish that in a 1/2 hour after the fuel tank was defueled.
I cringe at the possibility of removing a "ProSealed" flange with the fuel tank on the plane. The socket head screws weren't really necessary, either. The 3-1/2 oz. size of ChemSeal was far more than I needed for the plane, although I had enough leftover to seal up holes in a pair of shoes that ShoeGoo didn't fix, sealed some wires on a couple of ebike controllers, repaired a frying pan for the wife, and fixed a broken light socket.
So, take your pick, the gasket or the "ProSeal" both work, but with their own caveats. YMMV
They are the OEM gaskets installed in 2005 when I completed the plane. That's a pretty long service life of 16 years. Truth be told, I've had fuel streaking under each wing for the past 5 years or so that I attributed to leaking quick drains, but no fuel odor in the cabin until now. I searched the forums and found many suggestions to use "ProSeal", technically ChemSeal, instead of the gaskets.
I looked on vansaircraft website for the gaskets and couldn't find them right away and with uncertain shipping delivery times, I wasn't confident ordering from them with the time crunch I had. Since I'm much closer to Aircraft Spruce East, I ordered the ChemSeal 3.5 oz all in one tube. I defueled the plane, let it sit empty for a couple of days while I waited to receive the ChemSeal, mixed up the ChemSeal, replaced the #8 screws with #8 socket head screws as some suggested, placed a bead of sealant on the inside of the screws and the screws themselves, tightened them all down on both tanks, let them cure for 3 days (primarily because it was cooler than the recommended 77F degree curing temperature), fueled the plane back up yesterday, and, viola, no leaks. So, all told, about a 10 day downtime.
BUT, and this is the whole point of this post, was it really necessary to use ChemSeal? No, not with some fore knowledge and a little advance planning. The gaskets didn't leak for 7 to 10 years. Nothing lasts forever and if you consider the gaskets a life-limited item and just replace them every 5 to 7 years, you get the same, no leaks, result. The benefit is that the flanges were very easy to remove with just a stubby Phillips screwdriver. Should it be necessary to replace a defective fuel sensor, one could easily accomplish that in a 1/2 hour after the fuel tank was defueled.
I cringe at the possibility of removing a "ProSealed" flange with the fuel tank on the plane. The socket head screws weren't really necessary, either. The 3-1/2 oz. size of ChemSeal was far more than I needed for the plane, although I had enough leftover to seal up holes in a pair of shoes that ShoeGoo didn't fix, sealed some wires on a couple of ebike controllers, repaired a frying pan for the wife, and fixed a broken light socket.
So, take your pick, the gasket or the "ProSeal" both work, but with their own caveats. YMMV
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