[ddsmith]

Time for me to put in my two cents. Do not use the kits available at autozone to do the conversion. Do not use stop leak of any type in the AC system. If you want to know why check out the website that is linked for the POA adjustment. I installed a aftermarket AC system in my truck and regret that I just didn't know enough about POA adjustments and the availability of the parts I would need to make the system work in it's stock configuration. The only real difference being the refrigerant and oil. I got the certification to buy R-12 now and may keep some of my vehicle R-12. The cert allows you to buy R-12 to use. Your not allowed to vent R-12 to the atmosphere on purpose but you are allowed to make up to a leaking system all you want. ACkits forum is an excellent source of information about this subject. Highly recommended for inquiring minds. The vacuum pumps are typically not available to be rented but I have heard some have rented them from autoparts stores. I bought one to use since I tend to do all my own work. Good luck.