The most accurate way to charge any air conditioning system is to discharge, evacuate and charge the system using a recovery/recycling device approved for the type of refrigerant being used (whether R-12 or R-134a).
First measure the amount of refrigerant oil drained from the compressor into a graduated cylinder. Install the same amount of oil when reconnecting the compressor. A new compressor will have 7.25 fl. oz. (214 ml) of refrigerant oil already installed. Adjust the level through the suction port so it matches the level from the original compressor.
REMOVAL & INSTALLATION
- Disconnect the negative battery cable.
- Loosen and remove the belt(s).
- Using an approved R-12 or R-134a recovery/recycling station, follow the manufacturer's instructions to discharge the system.
- Disconnect the suction and discharge lines from the ports. Cap the lines and ports immediately to prevent moisture and dirt from entering the system.
- Disconnect the clutch wire.
- Remove the compressor-to-bracket attaching bolts and remove the compressor. It may be necessary to loosen the bracket-to-engine attaching bolts.
- Drain the oil into a graduated cylinder and carefully measure the amount. When installing the compressor, you will want to match this quantity of oil.
- Install the compressor on the truck and tighten the bolts to 20 ft. lbs. (27 Nm).
- Tighten the drive belts.
- Reconnect the clutch wire.
- Remove the caps from the suction and discharge lines and ports. Using new gaskets, install the lines to the compressor and tighten to 14-19 ft. lbs. (19-26 Nm).
- Using an approved R-12 or R-134a recovery/recycling station, follow the manufacturer's instructions to evacuate and charge the system.
- Connect the negative battery cable.