Air Conditioning problem
1993 GMC Safari 6 cyl Two Wheel Drive Automatic 20002 miles
93 GMc Safari. HAS a leak on evap side of dryer. R-12 is not cooling good anymore. Time to change to new refrigerant. Considering R-134a, hotshot, Freeze 12. With R-134a, do I need to replace dryer, replace expansion valve & orifice tube, flush evap. Condenser & lines, and drain oil from compressor( It's at the firewall, Ugly job, mirrors, stand on you head, strong arm, snake light & all ) replace all O-rings? If so, what size expansion valve & orifice tube do I need? Will R-134a work in a dual cooling system? The 134a kit has 2 oz. Oil + stop leak in each 12 oz. Can. Any estamates of how many pounds needed for a dual system? Any recommendations on which refrigerant is better? Big question, I'll have to get a set of metric flare wrenches, the dryer fittings are 32mm and the line side is 28mm, how big do I have to go before I can use open end wrenches? I asked a local shop, how much to evacuate the system & with each thing I told him, more $$$. He didn't want to just evacuate, so I'll have to do the dirty work myself & I want to do it right the first time.