lml@lancaironline.net Mailing List Archive

<<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> << Lancair Builders' Mail List >> <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> >> Andy wrote: <<persistent leak at the left wing root <snip> fuel probe fitting (pipe-thread type). <snip>? Any suggestions on fixing this problem will be gratefully received.>> Large diameter aluminum threads are notoriously easy to gall. Using pipe threads for this application was a bad choice on the part of the fuel probe manufacturer. Andy's problem can be fixed with a pipe tap and a tube of fuel resistant sealant. As I recall (please confirm this) the fuel probe uses a 1" x 11.5 Pipe thread. You will need to get a pipe tap in this size to chase the threads. If you can't borrow one, buy one from MSC (or your local industrial hardware supply) for about $30 (part # 04331096). There is only one flexible sealant that is appropriate to use around fuel. It is DOW 730 Fluorosilicone. "You can't use silicone around gasoline!!" you gasp. You are correct, this is FLUOROsilicone. You know you have the right stuff when you have to take out a mortgage to buy a tube (it is over $20 / oz.). A 3 oz. tube will set you back $66 but in Andy's case it is the only stuff that will work. This too is available from MSC stock # 00231605 (www.msc-direct.com). Normally you would only apply the 730 to the male threads but for galled threads I would recommend putting a thin coat on the female threads as well. Tighten the probe to about 20 foot pounds . Allow 24 hours before filling the tanks. Dow 730 also works great for patching fuel bladders and tanks, sealing fuel fittings and sealing engine accessories. Regards Brent Regan Buy American or don't complain when your job goes offshore. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> LML website: http://www.olsusa.com/mkaye/maillist.html LML Builders' Bookstore: http://www.buildersbooks.com/lancair Please send your photos and drawings to marvkaye@olsusa.com. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>