My son and I just finished up new nickel copper brake lines on his 51 1/2-ton with a new dual MC from Classic. It looks beautiful but every joint leaks between the new flare nut and the line.

I've tightened until i'm scared i'll strip the treads on something. ALL parts are new. The line and the flare nuts came from Jegs and a few of the brass fittings came from a FLAPS.

Now what?....Anyone else have this problem?