yeah whatever works.
Anyway quite seriously I dont recommend the manifold guages. Some may say this is outrageous, but I believe it to be true. Whats funny is that combinations of different fittings, the schrader valves and manifold knobs on various cheap sets can be mismanufactured and are actually blocking the R134 instaed of admitting R134.
I'm serious.
Even some good people dont understand the schrader functionality especially when you adding on the R134 adapters.
Sometimes you actually have to remove the schraeder needle points from your manifold hose lines--especially the middle line--because they are not "pressing against anything". Check your setup and think it through.
Also, I once had two sets of identical AC guages from Interdynamics. One set of knobs on one manifold worked the opposite of the set on the other manifold. I am serious.
I always get good results by thinking the system through and finding the low pressure side -- thats always the side thats accepting the return from your evaporator after it has done its "cooling thing" in your passenger cabin. The pressurized R134 gases have expanded and done their thermodynamic thing, and this expansion produces a huge temperature drop where the intensely cooled condenser sucks the heat and humidity out of your cabin...
Disassemble, flush and pull a vacuum on the system and feed the R134 straight from a can using one of those short discharge lines that come with the 16 ounce cans to the low side of the compressor on the LP tap. Use 2 16 oz cans. Those manifold guages? Unless you are a real pro and have really good ones, all they actually do is cause more trouble and cause leaks and allow the vacuum you have pulled in your system to escape. I always put my oil right into a hose when I have the system dissasembled and flushed.