I removed a piercing valve and soldered hole, after 6 months it came loose and leaked. I replaced the section of tubing and confirmed no leaks. In my haste to get this fixed I think that I did not leave vacuum pump long enough and there is some air in line because I loose heating to condenser and compressor just keeps running. I only applied vacuum for about an hour and I know better than that but was hopeful. All systems and fans etc. are OK so I assume there is some air and moisture causing a blockage in the suction side. My question is am I on the right track. Any advise would be greatly appreciated.

I obtained this unit free from a person that had a tech out for repair and he said it had a leak and was junk. The leak was difficult to find but was repaired but the were other issues that were addressed. Installed piercing valve for test purposes and after compressor replacement & filter/dryer left it there. Unit ran good for quite some time but another leak developed. That one was fixed and at the same time I remove the piercing valve and patched it over with silver solder. All was well for several months and the patch blew out so I decided to replace the section of tubing. Well now what happens is I can hold pressure for days but vacuum for short time, I can only assume that a little solder ball dropped off and is acting as a check valve or some other object. Gonna open everything and replace all the lines and blow them out with nitrogen and start over. There are no other issues except at the rear.
This is a personal battle for me and a learning experience, took as a project so it is my teacher so to speak. Gonna replace both dryers also. Refrigerant charge is weighed in on digital scale. All the leaks that were found were MFG defects, except the last one was my bad. Will post results soon