Hi everyone, new to the boards here. Hoping to get a hand with a problem I'm having.

1992 F-150 Custom, 300-6, M5OD, 4WD

My original secondary air manifold had very rusty ferrule nuts, and was leaking at about half of them (determined via bubble test). I ordered the PCI 412 manifold kit which includes new nuts.

After removing the original manifold and nuts, I cleaned the holes in the head, just with some oil and Q-tips so nothing nasty would make it into the head itself.

Then, I installed the new manifold and nuts, which was easier said than done. I lightly oiled the nuts both inside and out so that nothing would bind when tightening. I made sure that the manifold legs were in each nut as deep as possible, and it looks good compared to the original parts.

The only problem is, I did the bubble test again, and they ALL leak from inside the nuts! I tightened them all as tight as I am willing to. I think another even slight turn would break them.

What can I do about this? Any ideas are appreciated.

 

Bump.

Hoping to get some ideas before I weld the ferrules solid and move on.

 

What is a secondary air manifold?

 

He is talking about number 47 in the image below, the "Exhaust Air Supply Manifold":

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I sure am!

 

I wouldnt worry about it. Its just where the air pump injects air into the exhaust, right?

 

I could smell the exhaust coming from the original one because it was leaking. I'm trying to fix this properly.

 

I weld the ferrules solid and move on.

 

Have you inspected the check valve in the air tube?
If it's leaking, then exhaust would come out.