It may be that the reason you don't see any bubbles in the sight glass is that the freon is not passing which can be caused by different problems. One may be that the expansion valve is plugged up or the compressor has defective reed valves in it. The fans won't come on until you build up enough head pressure, not when the compressor starts. If you jumper the pigtails on the drier then the fans will run.
Check the compressor by putting gauges on the high and low side or see a competent AC tech.

TobiasMB
4 MBs