Installed new compressor/dryer pulled vacuum down. Recharged the system 81 ambient temperature got 30 +/- a few on the low side and 180 on the high. The air is getting cold its just the compressor will not kick in and out. I can't get the low side up anymore with free on. The low side line is very cold and sweats but the high side line is just warm not hot. When you add more free on, the high side just goes up. Low stays the same or drops a few psi. I changed the pressure switch, same thing. Maybe a faulty expansion valve?
I almost always replace orifice and expansion valves whenever I have the AC system open for any reason to keep from second guessing if they the cause of latter problems. That being said your numbers seem reasonable and it is blowing cold air... I am no AC expert but my goto book states that a restricted orifice will usually show as very low suction side pressure and lower than normal high side pressure. When the compressor kicks in, the suction against the restricted orifice will cause the compressor to quickly cycle out. After compressor disengagement, the rise in suction side pressure will usually be very slow. Rapid compressor disengagement and slow engagement may indicate a clogged orifice which does not sound like your problem but from experience, a clogged orifice tube will starve a compressor of oil. The expansion valve can stick closed, stick open, or hang somehwere in between but stuck closed is the most common. Gauges will show very low suction side pressure along with lower than normal high side pressure. The low side may even draw into a vacuum. Those that appear to be stuck closed may have inlet screens clogged with particles. It will look like sand packed into the inlet. The expansion valve can also stick open. This is indicated by higher than normal low side pressure, and slightly higher than normal high side pressure. None of these match what you are seeing, so my last words of non-wisdom is on my STS a few years ago, I had a computer problem that caused the compressor to run all the time. Just my .02 not adjusted for inflation
My numbers aren't bad. I am just wondering why the compressor is not shutting off. Of course if you let it run for a period of time, the air will get a little warmer.
38-40 is usually a good low side with R134 and around 190 on the hi side...... the compressor shouldn't cycle until the temp of the area you are cooling starts to come down in temp............ I would check the cab filter or evaporator coil if there isn't a filter... if either is dirty it will cause a lower than normal low side pressure. Same with the condensing coil ... in front of the radiator I'm guessing? If that starts to get to dirty the high side pressure will be unusually high. As you add Freon both pressures should rise together unless something is amiss.
If you had compressor failure I would recommend flushing the system with alcohol based flush and replacing the expansion valve, there is also a freeze switch in the hvac box that can cause the compressor not to turn on.