Mitsubishi Repair: Freon leak in 1998 Eclipse, freon gas, ac line

Question
I have a small freon leak at the location where the ac line attaches to the evaporator.  The mechanic thought that it just needed a new rubber o-ring but that didn't help. He has tried different size o-rings, a new ac line, etc. but nothing helps.  This originally appeared to be a simple problem but it is now driving everyone crazy!  Any suggestions?

Answer
Larry,
Freon leaks are tough to patch, since the freon gas is not only very small (molecularly speaking), but also to the fact that is can be under a great deal of pressure around 200-250 psi in the highest pressure of the system.  If replacing the line and o-rings does not help, your last alternative may be to replace the evaporator itself.  It's a pain to get to, but it may be your last option.
Good luck!