787 exhaust leak

[Nmskiguy]

The flange that is in this picture on the exhaust pipe right before the tune pipe if this is leaking and not sealed, can this cause running issues? And can I undo the flange and use some high temp silicone on it?

 

[WhiskeyD]

Replace the copper ring and follow the torque sequence in the service manual.

 

[etemplet]

I don't see a picture so my comment is only regarding the swivel pipe connection that uses the metal band to make up the the joint yes you can use copper sealant. I believe they recommend the high temp copper sealant which works well. If the copper gasket is not damaged I simply remove it and clean both sides and both sides of the exhaust pipe for a clean smoothing joint. I use a good amount of sealant. One thing you have to be very careful of is that the bosses come together evenly as you tighten the stainless clamp. You can tell by using a mirror and gauging the fit of the stainless clamp around the pipe as the distance should be the same all around. Be diligent.

*When looking at the copper gasket, if it is not deformed or damaged I reuse it (too expensive to replace and unnecessary) There is very little pressure in that pipe. If you have a leak there either the sealant is not applied correctly or the pipe bosses are not aligned. Diligence, proper materials and proper torque. Good Luck !!

This is a 951 if course and not your 787 but the only picture I have. The little short boss (protrusion/lip) can be a real bear to get and hold into position.

 

[mikidymac]

Also keep in mind that some of the copper gaskets have been discontinued so be careful with them.