Im looking for someone to tell me the correct procedures for servicing the Air-con on my 95 850 cause my local Air-con mechanic doesn’t know.

I took my car to my local Air specialist mechanic to service my A/c (basically regas or top it up) and to my surprise he rings me to tell me that hes unable to find the high pressure port and unable to do the service cause he s never serviced a volvo 850 before,so I said to him ill get back to ya after I found out.

So is there anyone out there that can tell me the technical way to service the A/c.
He needs to know how to totally remove the gas and the total refill amount, and the the pressures, associated with the job for hot climate conditions.

As Ive gathered if I lived in the US it would cost me as little as $10 and since Australia has federal laws and fines against buying in r134a cans from the US Id do it myself, so instead it’ll cost me $120. to basically top up the gas.

The mechanic tells me he'll remove the gas ,replace the r134a with new gas with a dye to check for leaks and replace the comp oil.(Not sure if the oil should be touched..after reading some forums.)

If Ive missed something out let me know.
Id appreciate it if someone out there with the wisdom or experience that could reply.

Thanks Mike