Injection line stuck to B-nut

[JonJay]

Here's a new one, and from the very experienced engine builders and mechanics, a new one for those I talked too.
While removing one of my injectors, I noticed some resistance above the normal break out force required to free the B-nut from the injector body.
In less than a quarter turn, the brazed fitting on the stainless line cracked right at the junction. Damage already done, I turned the stainless line into a pretzel before the line/fitting broke loose of the B-nut.

So, not sure what caused the fitting to stick to the nut to this degree, but a new line is on its way. Not sure what I would have done to prevent this, if anything.
Next time, if one sticks, and I catch it before it cracks, perhaps some mouse milk dribbled on the top of the B-nut, or some heat, or both.

Weird!

[Red Mtn flyer]

saw similar once, about 3 decades back. While deformities from removal made it difficult, we suspected failure of the ferrule - a crack or deformity - that then compromised the fit to the nut. Pressure, over time, made interference with the nut impossible to overcome. Like you, elected to twist-to-garbage, since cutting the nut would not have saved the line.
Airflow Performance stocks those at about $15 each, i believe - experimental only.
Skull sweat only, your results may vary.

[JonJay]

Originally Posted by Red Mtn flyer

saw similar once, about 3 decades back. While deformities from removal made it difficult, we suspected failure of the ferrule - a crack or deformity - that then compromised the fit to the nut. Pressure, over time, made interference with the nut impossible to overcome. Like you, elected to twist-to-garbage, since cutting the nut would not have saved the line.
Airflow Performance stocks those at about $15 each, i believe - experimental only.
Skull sweat only, your results may vary.

That makes sense. It is possible the crack I saw after a 1/4 turn was already there and not induced by turning the B-nut.
I also discovered the injector body was only finger tight. I may have loosened it in the process but I don't think so. I always put a wrench on the B-nut and injector body at each CI. However, if the line was frozen to the B-nut, it could give a false indication and fool one to thinking it was tight.

Anyway, line on order yesterday. They have gone up in price at about $35 now.