Recover any remaining refrigerant with approved recovery equipment
Turn off the engine and disconnect the negative battery terminal
Connect a manifold gauge set to the high- and low-side service ports
Attach the center hose of the manifold set to a vacuum pump
Open both manifold valves
Start the vacuum pump
Run the pump for 30 to 60 minutes, or until the system reaches deep vacuum
Close both manifold valves
Turn off the vacuum pump
Watch the gauges for 10 to 15 minutes to confirm the vacuum holds
If vacuum drops, locate and repair leaks before proceeding
Disconnect the hoses
Reinstall service port caps tightly
Reconnect the battery if needed