I am the process of rebuilding the fuel gauge on a L21B that I restored with a friend in 2015. We replaced the fuel selector valve the other day with a Dakota Cub STC'd (this Cub is a certified aircraft) unit and we noticed that the right fuel tank still showed some fuel after we drained both tanks in order to replace the valve.
I removed the fuel gauge thinking that it had a blockage at the bottom of the assembly. However, when I removed the gauge a small amount of fuel dripped out and the ball fell to the bottom (so I am still chasing that problem)--sorry I digress.
My question to you is can I epoxy the top fitting to the bushing that holds the glass tube in place??? I am having a problem getting that top fitting aligned so it points in the correct direction. It seems too loose or too tight. I already broke one glass tube while trying to get it lined up correctly (too tight). And I am afraid to leave it too loose because I KNOW it will leak. I have tried using different thicknesses of gaskets but I still didn't have any luck.
Also while I am on this subject---does anyone have a good process for leak checking the gauge before it is installed in the airplane. I have tried just filling the gauge up with av gas but I feel like I should put at least a few pounds of pressure on the gauge as well. How much pressure should I use??????
Any suggestions will be greatly appreciated.