Ok so you are correct in process as far as connecting the hoses to their respective (low/blue, high/red) side ports on the lines of the car and the yellow hose to the vacuum pump. during the evacuation process about 3/4 of the old oil will be sucked out of the lines and evap/condenser but not much will come out of the compressor.I'm not understanding what you're meaning here.
Here's the process as I understand it:
Connect the vacuum and gauges to their respective port, and run the vacuum for a LONG time (an hour should probably suffice to make my inner skeptic happy)
Once that is done, I turn the vacuum off and let it sit for like 15-20 minutes and make sure vacuum holds (if not, recheck the condenser fittings)
Once the vacuum is known to hold, pour the 3 1/2 oz of oil into the inlet hose of the gauges, and snap the r134a bottle RIGHT BEHIND IT.
So now, once I crack the refrigerant bottle, it should "suck everything up" into the system, no?
I thought I was leaving the motorcraft oil IN THERE, with everything else. Your response makes it seem, like I have to evacuate this oil, also? Are you talking about the oil that was "previously in there"?? If so, that kind of makes sense.
If so, then how does the "pressurized can" make better sense than the liquid oil? It's all about just getting it in, no?
Once you have allowed the pump to pull a vacuum for the hour you close both the blue and red valves on the gauge set before turning off the pump. Leave the yellow hose connected to pump and wait to see if vacuum holds.
If vacuum holds then you can disconnect the yellow hose and proceed one of two ways.
1) Measure out 3.4 ounces in a cup and immerse the end of yellow hose in the cup and open the red high side valve to allow it to suck the oil in and close the red valve just before it sucks in air, the messy way.
2) Or if you get the pressurized can of 3 ounces of oil then you disconnect the yellow hose from the pump and connect to the gold colored can adapter in the kit and screw the pressurized oil can into the adapter, then puncture the can with the valve on adapter ( you will likely have to unscrew the valve on the adapter to allow for the flow of oil/freon to occur) and open the red high side valve to allow the oil to be forced into the system by the pressure while holding the can with adapter at 6 o clock position, so all the oil is pushed out of can, then close the red high side valve and the puncturing valve on the adapter to seal the oil in the hose, the clean easy way.
If you blow thru the can adapter you will find which way is closed and which is open in terms of screwed in or out, I cannot remember which way is which at this time. I believe its counterclockwise to allow for flow and clockwise to puncture and seal after puncturing.
3) Then if you sucked oil from cup connect yellow hose to the can adapter and adapter to can of freon and open the blue low side valve on gauges to partial fill the system from pressure in the freon can again holding the can with adapter at 6 o'clock position till its empty, you will have to start the engine and turn on A/C ( max AC on high fan) to fully empty the can of freon then close adapter valve and switch to new can of freon and repeat.
4) If you choose to fill with pressurized oil can using the adapter, then close red high side valve and adapter valve and switch to freon can and open blue low side valve and adapter valve as above with can held upside down at 6 o'clock position till empty with A/C on as above. and repeat.
When both cans are empty close both adapter valve and blue low side valve on gauges and you should be done and can disconnect everything.
Hope this makes more sense. I just know what to do it sometimes get difficult to explain without missing steps or becoming confusing.
Feel free to reach out with questions.