Rick Britton Posted February 7, 2018 Report Posted February 7, 2018 On the pilot side of my M20F the under wing fuel tank drain/sample valve seats against a round stainless washer or plate fitting. There is a gap between the fitting and the threaded sleeve going into the fuel tank. Fuel has been leaking in this area so the drain valve was replaced and torqued to 30 inch#. Upon closer inspection the fuel is leaking from the backside of the round stainless plate fitting against the wing skin outboard of the fitting itself. Does anyone know what teh next step is to address the fix? Thanks
mike_elliott Posted February 7, 2018 Report Posted February 7, 2018 This happens when someone over tightens the quick drain. The threaded plate is riveted to the skin and the sealant breaks at the rivets typically. It appears like it leaks from the gap and needs to be "torqued" down more, exasperating the problem. IF this is what is happening to you, you will need to re buck those rivets and reseal the area.
Guest Posted February 7, 2018 Report Posted February 7, 2018 Mooney used a riveted drain fitting in early models which could be replaced with screw in valves per SB M20-188A. The stainless fitting you describe does not sound correct. This may help you, or post a picture of the valve. http://www.mooney.com/en/sb/M20-188A.pdf Clarence
mike_elliott Posted February 7, 2018 Report Posted February 7, 2018 4 minutes ago, M20Doc said: Mooney used a riveted drain fitting in early models which could be replaced with screw in valves per SB M20-188A. The stainless fitting you describe does not sound correct. This may help you, or post a picture of the valve. http://www.mooney.com/en/sb/M20-188A.pdf Clarence It is the rivets in #11 of SB M20-188A I was referring to. Great detail in the SB, thanks Clarence
Rick Britton Posted February 8, 2018 Author Report Posted February 8, 2018 Here is a photo of the fitting. When the drain valve is threaded in, fuel leaks from the backside of the stainless plate.
N201MKTurbo Posted February 8, 2018 Report Posted February 8, 2018 I think you are on your own with that. It looks like someone went rogue on that one. I suspect there is a nut washer and gasket on the back of that. Looks like a home made part.
kortopates Posted February 8, 2018 Report Posted February 8, 2018 Really looks like a hangar ferry gone wild. I hope it can be undone and fixed with the correct parts.Sent from my iPhone using Tapatalk
jamesm Posted February 8, 2018 Report Posted February 8, 2018 Is that a washer part of a fuel balder installation ? In wet wing fuel drain installation there is an o-ring that seal against bottom of the wing. At least from what I remember. MY IA did this SB many years ago. James '67C
Guest Posted February 8, 2018 Report Posted February 8, 2018 5 hours ago, Rick Britton said: Here is a photo of the fitting. When the drain valve is threaded in, fuel leaks from the backside of the stainless plate. Your plane has had the drain valve replaced, whether it’s fully done per the SB is a guess. It looks like someone bonded a washer over the rivets which hold the platenut to the wing skin. There appear to be no rivets in the washer. You may find that the riveting under the washer is poorly done. Or the wrong length of drain valve was installed and the washer is a shim. You’ll have to peel it off to find out what is under it. Clarence
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