BaldEagle Posted December 22, 2020 Report Share Posted December 22, 2020 The O-Ring listed in the Mooney parts manual does not fit my Shaw 431-9 fuel caps. Well, it does, but I am unable to twist the cap to close it. It seems that the fuel cap sits too high. The previous owner was using these: it has a lip on it. Anyone have a part number? Quote Link to comment Share on other sites More sharing options...
Vance Harral Posted December 23, 2020 Report Share Posted December 23, 2020 I've never seen a fuel O-ring like that. Not disputing that it "works", but it seems unusual/non-standard. The main reason I'm chiming in here is to point out that you can remove that cotter pin, and turn the nut, to adjust the spacing between the "stator" and "rotor" of the fuel cap. I'd bet if you turn the nut a few threads counter-clockwise, you'll find you can twist the cap to close it when the standard O-ring is installed. Keep adjusting until you get the desired feel, then re-install the cotter pin. If you're swapping O-rings, make sure you swap the little one in the center of the shaft, not just the big one being discussed here. 1 Quote Link to comment Share on other sites More sharing options...
Guest Posted December 23, 2020 Report Share Posted December 23, 2020 I’d like to know more about this seal. Anyone have details? Clarence Quote Link to comment Share on other sites More sharing options...
Raymond J1 Posted December 23, 2020 Report Share Posted December 23, 2020 For more information : https://www.airsafety.aero/ASSI/media/Documents/General/20151117_ALAD08_ASSI_Safety_Communication_Shaw_Aero_Devices_Fuel_Cap_Inspection_and_Maintenance_Issue_1.pdf 1 Quote Link to comment Share on other sites More sharing options...
ArtVandelay Posted December 23, 2020 Report Share Posted December 23, 2020 The O-Ring listed in the Mooney parts manual does not fit my Shaw 431-9 fuel caps. Well, it does, but I am unable to twist the cap to close it. It seems that the fuel cap sits too high. The previous owner was using these: it has a lip on it. Anyone have a part number? You don’t need to tighten the nut all the way down as shown in the pictures, tighten enough to fit the cotter pin, try it, keep tightening until you have a snug fit. 1 Quote Link to comment Share on other sites More sharing options...
Hank Posted December 23, 2020 Report Share Posted December 23, 2020 Time for real information from the expert: @OSUAV8TER, got your ears on? I bought a set (2 big uns, 2 lil'uns) of blue fluorosilicone o-rings from him, going strong as they approach 3 years of age. They ain't got no flat edge on em . . . . And yes, you need to adjust the nut and test fit the cap / plunger several times to get it right, then put in the little bitty cotter pin. 1 Quote Link to comment Share on other sites More sharing options...
RLCarter Posted December 23, 2020 Report Share Posted December 23, 2020 2 hours ago, Raymond J said: For more information : https://www.airsafety.aero/ASSI/media/Documents/General/20151117_ALAD08_ASSI_Safety_Communication_Shaw_Aero_Devices_Fuel_Cap_Inspection_and_Maintenance_Issue_1.pdf Looks like these are for the Shaw 416-50 caps, yours are 431-9 in the picture. You also said you got the part number from the Mooney Parts Manual? Quote Link to comment Share on other sites More sharing options...
BaldEagle Posted December 23, 2020 Author Report Share Posted December 23, 2020 It looks like what I have are “lightning proof” fuel cap o-rings, which makes sense as my J was previously based in Florida. It is approved for installation on my J by serial number but only if I have the O&N bladders (I don’t) or have Shaw 457 fuel cap (I have 431). So to be legal I think the only option is to use the part specified by Mooney and adjust the fuel cap nut as mentioned previously to make it fit so that I can close and latch it. And to be ultra cautious, pressurize the tank to 1/2 PSI per the SB to check for leaks. https://www.mcfarlaneaviation.com/products/product/CA38241/ Quote Link to comment Share on other sites More sharing options...
Nokomis449 Posted December 23, 2020 Report Share Posted December 23, 2020 As Hank mentioned above, I bought and installed the same blue O-rings (2 big uns, 2 lil'uns) 2 years ago and and they're a winner. Don't have the link on me, but maybe someone does. I like supporting MS'ers who are helping us maintain our aging fleet. Quote Link to comment Share on other sites More sharing options...
tmo Posted December 23, 2020 Report Share Posted December 23, 2020 @OSUAV8TER is the source - https://www.gallagheraviationllc.com/products.html 1 Quote Link to comment Share on other sites More sharing options...
RobertGary1 Posted December 23, 2020 Report Share Posted December 23, 2020 Since the seals get replaced at each annual I just buy 1/2 dozen at a time at spruce. Quote Link to comment Share on other sites More sharing options...
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