Fixing a Grumman Fuel Tank Leak
How I Spent My Summer Vacation

Enough people have asked me about my recent fuel-tank repair project that I figured it's time for a web site. This is the result.

Me? I'm Bluejay Adametz, and I've owned the subject Tiger since 1986 (with a little help from a bank). I've also been an A&P mechanic since 1992, which is real handy if you own an airplane. Someday I hope that the money I save by doing my own work will exceed the cost of the schooling, books, and tools.

Uh oh...

During the 2002 annual of my 1979 Tiger, we discovered the telltale signs of a fuel leak in the area of the outboard tank rib in the left wing. Examination of the plumbing, bonding and the area around the spar led directly to that dreaded conclusion: my wet wing wasn't wet just on the inside anymore.

At first all the horror stories I heard about persistent leaks, thousands of dollars spent, etc... came to mind. Several people remarked that the leak wasn't really bad enough to worry about. I knew in my heart, however, that it wouldn't get any better, and if something is broke, I want to fix it. Besides just being good practice, it would probably get worse at the most inconvenient time.

I considered several possibilities. While I've been around Grummans for many years, maintaining my own Tiger and various Grummans belonging to friends, I don't consider myself to be an especially gifted mechanic. Then again, I am licensed to do this sort of thing, and the biggest risk would be the cost of my own labor if my repair didn't work out and I ended up sending the job to the experts.

Below you'll find an overview of the process. Links will take you to more detail.

More information

If you're looking for more information or contemplating this repair yourself, the first thing you need is the maintenance manual. Aside from keeping the FAA folks happy, reviewing the relevant parts of the manual will give you a clearer idea of what you're getting into and allow you to proceed with confidence that you're doing it Right.

You'll also need a licensed airframe mechanic. No way that I can read FAR 43 appendix A lets me think that this job even might be preventive maintenance. However, being that this is a project that calls for a lot of raw labor, it is a good opportunity for the savvy owner to work with their mechanic and save some real dollars.

I strongly suggest you join the Grumman-Gang mailing list (go to http://grumman.net). Myself, and a number of very knowledgeable and helpful individuals hang out there.

The folks at Fletchair in Houston, TX were also invaluable as a source of parts, materials, and advice. Check them out at http://fletchair.com. A number of Fletchair people are also frequently seen on the Grumman-Gang list.

Let the fun begin...

This first batch of pictures shows the "before". Things have been opened up and the initial reconnaissance has been done. Picture of partially-dissasssembled airplane
More before pictures
After the first 1/2 day of work, I was still wondering what I had gotten myself into and didn't have a lot of momentum. So I decided to stop and take some pictures of the progress so far. Picture of inside of the tank, top/aft of spar
More day 0.5 pictures
By the end of the first day, the process of cleaning out old sealant was pretty much under way. Picture of inside of tank, aft of spar, showing old sealant scrapings
More day 1 pictures
Day 2 was more scraping. Picture of inside of tank, top/aft of spar
More day 2 pictures
Day 3 was still more scraping. Daylight is beginning to show. Picture of inside of tank, top/aft of spar
More day 3 pictures
Day 4 was more scraping. There can't be much more old sealant in there. In fact, at this point the cleanup is declared done. Picture of inside of tank, top/aft of spar. Old sealant removal is done.
More day 4 pictures
Day 5 and the fun begins. The new sealant is gooey, sticky, and anything else that can make a mess. Picture of inside of tank, top/aft of spar, with new sealant applied
More day 5 pictures
We let everything sit overnight and started putting in fuel. Pictured are a few of my favorite tools. Picture of scraping tools
More day 6 pictures
Ooops. It seems that sitting dry for a couple of weeks didn't do the old quantity sender gasket any good. At least this leak is at the opposite end of the tank. In fact, it appears that it may have been leaking for some time, just not enough to drip. Picture of new leak at fuel quantity sender
More day 7 pictures
Finally back together, signed off, and ready to fly. You'd never know anything had been wrong, except for the logbook entry. Picture of airplane with repair completed
More after pictures


It's been over 10 years now without any sign of leaking. I think maybe I got it. Viewable with any browser