A/C no longer cooling?

Attempted last year to fix A/C after taking car back from mechanic shop - due to low estimate that continued to climb.
I rebuilt the upper engine (rockers, water pump, belts, etc, after a rocker broke). Unfortunately for my son they disconnected the AC system to do their work. Sadly, most sites indicate that it is not necessary (but it does make it easier for them and cost more at the final bill).
Issue - blows mostly hot air.
Gauges installed - you can hear the compressor kit in repeatedly as the pressures change.
Low side pressures go from 30-70 as high goes from 125 -150.
Do I have a leak in the system or is it an A/C switch or expansion valve stuck open?
Last year I replaced the drier but not the expansion valve in the pipe running to the drier. I evacuated the system and recharged it with 2 cans of R134 (using a scale).