How can you vacuim the ac lines on a 97 Audi quattro?

To vacuum the AC lines on a 1997 Audi Quattro, first, connect a vacuum pump to the high and low service ports of the AC system. Make sure the system is off, and then run the vacuum pump for at least 30 minutes to remove moisture and air. Afterward, close the valves on the pump and check for any leaks. Once the vacuum holds steady, you can proceed to recharge the AC system with refrigerant.