I have a 95 Corolla that had an AC leak in the condenser. I replaced the condenser and drier. Then pulled a vaccum on the system for the recommended 30 minutes. I then added 2 cans (12oz) of R134a. Now, when I turn the AC on, the system pulls a vaccum on the LP side and the HP side remains at about 140 psi. What are the likely causes of this? Before the condenser failed, I had not had any troubles and the system was nice and cold. A used compressor was installed about 5 years ago.
If LP reading is abnormally low, check if the low pressure hose and metal end areas are cooler than evaporator. If yes, you have clogged or kinked low pressure hose parts.
If the temperature around the expansion valve is too low compared with that around receiver drier, the high pressure line is clogged. It could be a failed expansion valve. During discharging prior to repir, if pressure had been released too fast, it can damage the expansion valve.