Hatz Biplane Association

Our sight gauge has developed a small leak over the long winter. It is leaking at the very bottom of the tube around a plug similar to the one shown in this photo from the old forum:

If I remove the plug, and no cracks are visible in the tube itself, is there a tape or dope I should re-install it with?

A product called TiteSeal in the threads probably would help. It is sticky, never drys or hardens and is not affected by gas or oil. It is available from AS&S or maybe NAPA. We have the Piper PA-12 style guage and it cured our seepage problem.
John Hanson HC-012

What timing that you would post this. Two days ago, Saturday, I drained most my avgas because my sight gauge too was leaking. My gauge is like the picture, from AS&S. First leak in five winters, maybe that is as much cold as it can take. I was going to try Permatex Aviation Gasket #4, as it says good for threaded fitting. But since John recommends TiteSeal, that will be my first choice, thanks John. If it still has seepage, I may switch to a PA-12 style fuel gauge.
Hurry up Spring-time. Herb

Hi, Jim Pinkerton hear from CO. I had the same problem with this site gauge and finally unscrewed the plastic site gauge and placed a small O ring in there, it just seamed like one should have been there in the first place. I called Aircraft Spruce twice on this matter and of course no one ever responded. It works fine now. Jim

2 watch fors if you try the Tite Seal route. It's label warns against using it with Plastics. From the picture I cannot tell if you tube is glass or plastic. The other, is that Tite Seal is not alcohol proof. Could be a problem if you are a car gas user.

Lyman