R134 A/C conversion

[scottfab]

Originally Posted by LantanaTX

Never had to replace a dryer before when doing this, but the system must be evacuated before charging.

Actually you can even forgo the evacuation (coming from multiple experts, shops and my own experience) if the system has not been left open long, especially if a new dryer is installed. It takes out moisture.
It's like turning the rotors for a good brake job.
You don't have to, and you may get away without doing it a time or two
but a good brake job says, yah, ya need to.

PS all this applies if you simply adding R134a to an existing R134a system. If you're converting from R12, oh boy. A completely different animal. Been there done that.