Not sure about that, if he had a vacuum pump or not. I remember, back in those days when I asked for a full AC service, he took out pretty much all of the AC components -- condenser, dryer, compressor, evaporator, pipes -- changed the dryer with new one, washed the condenser and evaporator, cleaned the compressor and while putting it all back poured a little compressor oil in it.
Then started filling Gas via desi compressor & gauges (those little back compressors than run on 220V, I've seen in refrigerators/water dispensers
)
Not sure, if that compressor worked as vacuum pump or not 