Auto Air Conditioning & Heater Repair: a/c guage readings, control valve, accumulator

Question
I converted my 1987 Fiero 2.5L to r134a.  I replaced the V5 compressor and control valve, accumulator and orifice tube.  My question is I have read that I should only put 90% r134a in the r12 system, so what should my gauges read.  At max air my low side is 35 and high is 250.  Does this seem right?

Answer
Hi Tom

If you put 90% and you have those pressures you are good.  Depending on ambient temperature some areas can only put in 80% of the charge.  Your system should be cooling if not then add just a little bit more and hold suction at about 40-45 psi and high will be 250-275 psi.