I have an 89 f-150 I am retrofitting to 134a. Everything has been replaced and flushed and a vaccum applied.
What is the correct charging procedure. I have seen those temp/pressure charts but do not fully understand them. Example: 134-a at 75 degrees has a pressure of 78. Someone told me that this means an outside ambient of 75 degrees should produce a pressure on the low side of 78. This does not sound right to me. 78 seems awful high or am I missing something?