Air Conditioning Clutch

[stope4]

Just installed a new rebuilt a6 compressor, expansion valve, new oil, new hoses, conversion to 134a freon, and all new seals. The original compressor was making noise, one hose was leaking and I didn't know what was in the system. Now that I have made the conversion, the compressor clutch does not shut entirely off when I turn the ac off from the switch. It starts to disengage but it makes a funny sound and after about three or four seconds disengages entirely. The funny sound is the clutch disengaging slowly. If I unplug the compressor, the clutch disengages immediately, the way it's suppose to. I replaced the diode thinking that was it but no cigar. Does anyone have an idea as to what can be causing this?

Oh yea, it's a 71 chevy, 402, original factory ac and I did not notice the other compressor doing this.