Auto Parts: Retrofitting a A/C r-12 to r-134a, compressor clutch, oil charge

Question
Hi

I have a 1993 chevy c2500 with the 350 motor that I just completed a motor swap on and now im down to the A/C system and I need to know if theres anything I need to change over besides the oil in the system to convert it to the r-134a ? Also if I decide not to retrofit it immediately is it going to ruin the A/C compressor clutch or any other parts if I drive the truck with out the refrigerant in it? Should i Disconnect the lines from the compressor?

Thank You
Bruce

Answer
Hi Bruce,

Running the engine w/o A/C refrigerant isn't a problem as the receiver/drier needs a specific amount of pressure in order to operate the pumps clutch activating the system. If the system is empty, you'd have to manually splice the clutch ground wire to operate the pump.

The high and low side connectors have to be replaced also, if you got a change-over kit, these should be included. ALWAYS add the 8oz. oil charge FIRST while the engine is running and the A/C control on HIGH or MAX. The manufacturer will recommend you fill the system with the cans upright, but the oil charge is BEST filled with the can inverted. Actually, ALL of the refrigerant will fill faster with the cans inverted, the reason that you keep the other cans upright is so that the pressure on the LOW-side does not increase too quickly and cause it to rupture. If you disconnect the lines from the back of the compressor, you will have to replace the O-ring seals, so if they don't need disconnecting, and they are not leaking now, leave them alone.

Thanks for the question, I hope this information was helpful to you.
Fred
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