7KCAB Fuel Gauge Leak

R

RobertEdwardAnderson

New member
We have a 72 KCAB that the fuel gauge has begun to leak a drop at a time. Our A&P has tried to replace the gaskets twice but can't seem to get it to stop leaking. Does anyone have any ideas about something different we should try or should we just try a new A&P experienced in this type of work. Anyone know of any in the central or southern Ohio area?
 
It's hard to tell without looking at it. There were 2 different gauges used, one had E, 1/4, 1/2, 3/4, F on a rotating indicator and the other one was a Rochester that had a pointer indicating the fuel level. Don't know which you have but I think they both are aluminum and have a flange with 4 screw holes. The flange can get bent inward over time, and over tightening to stop leaks. If this is the case, remove it and file the flange flat so the "ears" where the screw holes are are not bent inward.
 
This one has the rotating indicator (drum). We are getting a drop of fuel off of the bottom of the gauge face every 20 seconds of so. Your suggestion was an excellent one. That may indeed be why our mechanic could not seem to solve the leak with just the gasket replacement. Thanks.
 
I have the rotating drum gauge like yours. I did not like the gaskets ACA sent me. They were very thin and did not seal. I purchased gasket material that is about 1/16" thick at an auto parts store and cut my own. This material was about twice as thick as the ACA gaskets. A gasket goes on both sides of the gauge flange. Clean up everything with solvant. Put a thin film of Gasoila sealant (for use with gasoline) on both sides of both gaskets. Put a layer of sealant on the tank bung flange. Reassemble: gasket, gauge, gasket, glass, nut. Hand tighten, make sure neither of the gaskets have rolled and that nothing is touching the drum by visual inspection. Tighten another 1/4 to 1/2 a turn with channel locks. Then let it sit a day before putting gas back in it. Have someone else put gas in while you watch the gauge to make sure it comes up smoothly and is not hanging on anything. I'm running mogas which is more obvious when it leaks (smell and visual). It's been over a year. This procedure fixed mine.

While you have the gauge out might as well solder a new cork float on. It's a standard bottle cork. I think it's a #5 cork.
 
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