i faced similar problems with my charade, it also had an r12 system.
before i knew much, normally had it charged with r134a desi method. and ac was serviced each year.
found an r12 guy after a long time, but then the system had leakages.. so just made do till i sold the car.
the 96 civic i have now was serviced only once by sabir bhai 3 years ago. since then its working as it should without any problem
i understand you are stuck when your car is open at the workshop and you have no parts or equipment.
after learning my lessons, i collect all possible required parts/equipment first. then go to the shop to work on the car.
