Ford has designed and tested specific retrofit kits for their vehicles. They are the most comprehensive kits available from any vehicle manufacturer
All retrofit procedures must follow SAE guidelines. Ford retrofit kits are designed for specific vehicles and have been tested to provide performance equivalent to R12 performance. Detailed retrofit procedures are provided with each retrofit kit.
I have been told that Ford Motor Co. has to pay their car dealers for a retrofit if they can not supply R12 while the vehicle is covered by extended warranty. This may be why they hold so much R12.
All Ford retrofits include a CPS (cycling pressure switch) kit, a RCS (refrigerant containment switch) kit, PAG oil, R134a service ports and service label. Recommendations From A/C Shops and Aftermarket: On systems that control the evaporator pressure to control the evaporator temperature, lower the minimum pressure with R-134a. This is because the pressure temperature relationship of R-12 and R-134a is different. For instance at 25