Exhaust Leaking Past Pyro Fitting In Exhaust Manifold

[PKleine]

It finally happened, after about 35k miles I broke something on my Cummins. I was exiting off I-5 down a steep grade where the sign said for trucks to use lower gears. So as I slowed I put her into 3rd ~3100 rpm and the exhaust brake gave its all. It's been whistling ever since.



As it turns out, the exhaust is escaping past the 1/4 npt bushing in the exhaust manifold mostly along a short section facing aft. The taper seems to be gone as the bushing will bottom easily. Anyone have an idea of how I can get the threads to seal again?



Thanks in advance.



Peter

 

[CarlJensen]

Get a new bushing and use the Permatex copper anti seize on it.

 

[bgilbert]

You can weld the bushing to the manifold. Thats what I did when I tapped too far.

 

[Tcolesanti]

Just get a new brass fitting, you should'nt have messed the threads up in the cast iron. If they are messed up, take the manifold off and have it welded like bgilbert said. Or, buy an ATS manifold, that already hase a boss to drill and tap for a pyro.

 

[PKleine]

Wednesday morning it stopped raining long enough for me to go after that pesky whistle. The bushing is not loose in the exhaust manifold, its more like it is seized. I didn't press the issue because that afternoon we needed to be on the road until late next week. I guess I'll just have to get used to the whistle for now...



Thanks for the responses, I was going to try the copper anti seize first. I hate the thought of having to replace the exhaust manifold.



PK

 

[RRoton]

You can fix it with "FIRESEAL 2000"

It's good for up to 2000 deg F

http://www.por15.com/