740 1992 R/12 compressor replacement

[josepe]

ac blowing ice cold then compressor suddenly locked up - bought an exact identical used compressor off of the same year and make car - took off the old compressor,dryer and orifice tube-flushed system-put 2 oz of r-12 oil in new(used) compressor after emptying out all the old oil and 1 oz in new dryer-installed new o-rings and then new compressor, new dryer, and new orifice tube-vacuumed system for 1 hour then tried to charge but it will only take .5(1/2) lb and is not blowing very cold - also the high side line is frosting up from the firewall down to the orifice tube and the low side line and dryer is getting hot. I was told by a friend who has the equipment and is supervising me that it should be the opposite and the high side line should be hot and the low side should be cold-he also told me to only put in 3 oz oil since the radiator looking thingy and the rest of the system would still have some oil left in it even thogh the back of the compressor says aprox 6 oz. Maybe I installed the orifice tube backwards? Or could it be the wrong one? There is an arrow on orifice tube. Should it point to firewall or front of car. I was also told to try a variable orifice tube since I live in Florida but I thought that was for when you are converting to 134 which we are not doing. My friend has an old machine and lots of R-12 left over from years ago so we are only putting the system back the way it was. When using the old machine we put the low side line on the port at the dryer and the high side went underneath where there are 3 switches in a row. I used the far left one (drivers side) sorry to ramble but want to be as specific as possible so you know exactly what I'm doing. Any help would be much appreciated and maybe this will help others trying to do the same. Thanks!!!!