Fuel Pump Fittings

[skelrad]

Educate me - on my fuel pump lines from Aircraft Specialty, some lines have nuts with the sleeves, and some have nuts that have no sleeve. Why the difference? For example, this line going to the pump - one end has a nut/sleeve and the other end just the nut. The line going forward from the pump to the firewall also has no sleeve. Do not all flared fittings require that sleeve for the nut to compress against the flare?

 

[TS Flightlines]

Educate me - on my fuel pump lines from Aircraft Specialty, some lines have nuts with the sleeves, and some have nuts that have no sleeve. Why the difference? For example, this line going to the pump - one end has a nut/sleeve and the other end just the nut. The line going forward from the pump to the firewall also has no sleeve. Do not all flared fittings require that sleeve for the nut to compress against the flare?

View attachment 79594

Hi Brandon, YES there are sleeves under the nuts. In order to make the very tight bend, we shorted the tail of the sleeve, but it still supports the tube behind the flare, at the flare, and gives the surface for the nut to rotate on. It does not effect the performance of the nut, sleeve, or tube.
Tom

 

[skelrad]

Hi Brandon, YES there are sleeves under the nuts. In order to make the very tight bend, we shorted the tail of the sleeve, but it still supports the tube behind the flare, at the flare, and gives the surface for the nut to rotate on. It does not effect the performance of the nut, sleeve, or tube.
Tom

Ahhh, I see! That makes perfect sense. Learn something new every day!

 

[TS Flightlines]

Ahhh, I see! That makes perfect sense. Learn something new every day!

Brandon---a little secret----by shortening the tail of the sleeve, you can push the sleeve AROUND the bend of the tube! That means you can make the leg length of the tube as short as your bender and flare tool can do it.

Tom

 

[skelrad]

Brandon---a little secret----by shortening the tail of the sleeve, you can push the sleeve AROUND the bend of the tube! That means you can make the leg length of the tube as short as your bender and flare tool can do it.

Tom

Oh man, I wish I had known that secret a while back! I can think of a number of places where that would have meant the difference between a really nice end result vs my actual result (you know, the face only a mother can love kind of result).