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Leaking Fuel Sight Gauge

Big Ben

Registered User
Ripon CA
I have been seeing some blue residue on the fuel sight gauge. When I filled up today, I noticed that there was a slight leak where the glass (?) meets the aluminum near the bottom. Full fuel makes it leak more.

Do I have repair options or replace? How long does it take, what is needed and are the original gauges available if there is no repair option? I leave for Lompoc on Friday and need your advice/help. Thanks, Ben
Dont mess with it before ordering the new cork gaskets and balls. Then take it apart. Clean glass with acetone and scoth brite. Might order new brass threaded bushings as they are probably cracked. Do not put too much fuel lube on cork gaskets or the balls will get stuck to them
Yup what Mike said and if you flip between mogas and avgas they will probably start leaking .
I fought sight gauge problems for a few years. Then I switched to the Dakota Cub sight gauge and problem solved. The Dakota has O ring seals not cork gaskets like the Piper sight gage and the Dakota seem better built.

Jerry Jacques
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I bought a set of these sight gauges. I haven't installed them yet but I will say that they look very well built. I believe that I will be glad that I purchased them.
Thanks all, I tried to rebuild with old gaskets as the new ones did not arrive (bad idea that did not work). All my cub buddies flew down to Lompoc this am and parts just arrived!! Going to the airport to tear it apart again. Any suggestions on how tight to tighten he ends? Thanks, Ben
Also check the bottom & top of the glass tube(s). I've seen a few that were very rough. They leaked only when tanks were 3/4 to full. After sanding the glass smooth, and the new gaskets . . . we were lucky . . no leaks. Larry C.
My bad seems like its always the bottom one leaking, guess there's a reason for that Daaa
Thanks all, I did get two cork gaskets. The glass did have a slight chip which I sanded out. I used a small amount of fuel lube and all went back together great. No leaks and a new bright orange float ball. I did "try" to wait for the parts to arrive as advised, but patience is not my virtue :lol:. Two good things did come from this, I have twice the experience fixing this problem, and #2 I pulled the fuel tank cover to discover the aileron cable had been mistakenly routed under the threaded end of the fuel tank strap causing it to rub. I fixed both problems! Thanks again! Ben
... I pulled the fuel tank cover to discover the aileron cable had been mistakenly routed under the threaded end of the fuel tank strap causing it to rub.... Thanks again! Ben

i put masking tape as shown after installing tanks with wings off, to help make sure that don't happen... once ailerons are installed and cable is tight it don't touch the tape.. (I put tank covers on before wing install...)