* Recovery/recycling machine capable of recovering R12 without venting it to atmosphere
* R-134a refrigerant
* R-134a oil
* O-rings
* Schrader valves
* Vacuum pump
* Refrigerant manifold gauge set
Step 2: Prepare the vehicle.
* Remove any accessories or components that could obstruct access to the air conditioning system components.
* Disconnect the battery to prevent any short circuits.
Step 3: Recover the R12 refrigerant.
* Connect the recovery/recycling machine to the low-pressure port on the air conditioning system.
* Turn on the machine and let it run until all of the R12 refrigerant has been recovered.
Step 4: Evacuate the system.
* Connect the vacuum pump to the low-pressure port and apply vacuum until the system reaches 29 inches of mercury (Hg).
* Hold vacuum for at least 30 minutes.
Step 5: Replace the O-rings and Schrader valves.
* Remove the old O-rings and Schrader valves from the air conditioning system.
* Apply a light coat of refrigeration oil to the new O-rings and install them in place.
* Install the new Schrader valves.
Step 6: Recharge the system with R-134a refrigerant.
* Connect the refrigerant manifold gauge set to the high-pressure and low-pressure ports on the air conditioning system.
* Turn on the refrigerant manifold gauge set and open the high-pressure valve.
* Add R-134a refrigerant to the system until the pressure gauge reads 250-300 psi.
Step 7: Test the system.
* Start the engine and turn on the air conditioner.
* Verify that the air conditioner is blowing cold air.
* Check for any leaks using a refrigerant leak detector.
