So , i fixed a brake line leak . While under the hood the 2 lines from the master cylinder to the booster? Looked pretty bad so i bought 2 new lines from autozone . Had bubble flares on all 4 connection points so they gave me brass adapters to mate up to the lines i bought .

The connection in the master cylinder closest to the cab cross threaded . The MC seems aluminum ? The adapter brass . I dont know if i grab a new adapter and try again or if i damaged the threads past being effective .

Whats my best course of action ? Its just a lot truck for winter plowing on my driveway so im not agianst a crazy fix . Thank you .

 

Maybe a helicoil in the M/C and a new brass adapter?...Just guessing since it's never happened to me (knock wood)......Ben

 

Because of how the inverted flare in the master cylinder port sticks up, I doubt the OP could drill down far enough to fully drill for the helicoil - so its likely the insert threads wouldn't properly meet the remaining original threads and he wouldn't be able to fully seat the tubing and tubing nut. For the degree of hassle involved in trying to helicoil the master cylinder, I think I'd just buy a reman MC and another adaptor, and be more careful about starting the tubing nuts. As far as the flare styles - did AZ not have standard double-flare tubing?

 

Usually, you can chase the damage from the bottom out with a pick. Being very careful get the entry point correct and tighten it up.
Of course, you can try again.

M

 

Another possibility, assuming you can get far enough into the MC port, is a "back tap", like - you would need it in the proper size & thread pitch, of course - which could be determined from your adapter. Other than the size/pitch availability, the big question would be whether or not you could get past the damaged thread and engage clean thread to work it back out. I've only seen these listed for spark plug thread sizes, though.