Angelo,
I was working on my 2000 Z71 OBS Tahoe and came upon the same probelms. Had it been a customers, I would had to charge for new condenser and rear A/C line. My fitting were also seized together, and even after heating them up, I could not break them free!!! Then I tried to bypass the "Y" to the rear A/C with a stock line from the dealer that bypasses the Rear A/C, but couldnt get the fiting free, so what I did was cut the line BEFORE the Y and installed a compression fitting!! Guess what, IT WORKED!!! I avoided having to buy the complete rear A/C line and all the work. Only bad thing is, I dont have Rear A/C, but I dont care, im the only one who drives my truck and the rear guys can suffice with normal A/C! Dont jump your technician so quickly, especially if hes helped you and your friends in the past!!! Alot of us techs out there are honest, its the bad ones that put us good honest ones a bad name!!!