First, have someone evacuate the refrigerant from the old system. .
Physically remove the old compressor, rubber hoses and the receiver/dryer. Also plan to replace the expans…ion valve, you may need to search for it but it's often at the bottom of the condenser, right where it connects to the hose that leads back to the passenger compartment. .
Often the old compressor starts to blow chunks and you end up with debris in the refrigeration lines so you'll want to examine the oil, if it's black or anything but clear, run a "flush" solution through the remaining lines until it comes out clean. Blow it all clean with compressed air that's gone through a dryer. .
Reassemble refrigeration system using new hoses, expansion valve and compressor. .
Vacuum test the system to check for leaks and to remove any traces of water. .
Recharge the system using 134A refrigerant and the approved oil charge either adding the exact amount of refrigerant called for in the specifications, or using a gauge set you can determine when the AC is fully charged. (MORE)