Same prob with my recently acquired 81 300D. No belt on compressor; compressor does not turn. Got new compressor (R4, $295) & dryer ($55) from ADSIT month or so ago. AC tech planning to replace units next couple of days or so (ASAP). I'm keeping R12.

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Wilton Strickland
Goldsboro, NC
91 350 SDL. 81 300D