dyoes said: I know you said you didn't want to replace the front to rear line, but if it's original to the car, you may want to bite the bullet and do it. That's where I found mine patched from an earlier leak. I did it with the body on the car using 3-ton jackstands. Not easy, but not as hard as I thought. If nothing else, you may teach yourself some new swear words.
If you're going to replace it anyway, and at the risk of seeing the real mechanics in the room cringe, I've gotten some old lines off intact with smooth jawed vice grips when all else failed. Once the fittings start rounding, it's almost game over even with a good quality fitting wrench. Use a 6" or so smooth jaw vice grip, clamp it down tight and go for it. I've never had the fitting break off, although it'll likely be deformed and unusable when you're done. But you'll save the block.
Good luck to you.
Just reviewing this post again as I tried again to get these fittings loose with no luck, decided to leave the block in and see if it leaks. If it does I'll worry about it then. I also tried to figure out how to replace the front to rear line while my car is on jack stands as you said you did, but I cant see how you did it. I have a 72 with a manual transmission so the crossmember is welded in place, the brake line also snakes through the rear cross member. I dont see how you can snake a pre-bent line through there, any hints? Tried from the front first, then from the back first, no luck! Perhaps with more clearance under the car as with a lift it could be done. Am I missing something?
Also - anyone have any problems with replacement lines from Corvette America? I bought a stainless rear crossover line and it is clearly too long to fit between the two blocks. Any suggestions on where to get one that will actually fit?
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Mario