May I add another wrinkle to this question? If one is using a vaccuum pump to draw down the system after a part replacement, both valves are open on the gauge set during the vaccuum. After the process is done, then both valves on the gauge set are closed, and the pump is shut off and disconnected. May I assume that purging the fill line at the gauge set after attaching the can of R134 will suffice? Since the low side line is in a vaccuum state, would it be unnecessary to somehow purge it also?

Thanks in advance...

__________________
Bob Johnston
03 E55
Comand/Nav/Bluetooth/Ipod added
Black/black
(Oh man, this car is sooooo fast.)