Last year I converted from R12 to 134a. I thought I did it right. I replaced the compressor, reciever/dryer, and the expansion valve. I did a presure test and then recharged the system with 134a.
Being that I did not know how much freon to put into the new system, I just pretty much went by the sight glass and how it felt inside.
Well it's been almost one year exactly sence the convertion and now my compressor is starting to make noise. Afew days ago it started blowing hot. After messing with it for a while I found out that it was overcharged and the compressor was locking up. So I drained the system until it was low enough that the compressor wouldn't kick on. I then put in one 15 oz can of 134a and it seemed to be working fine. Then today it started blowing hot again. But this time I can't seem to get the compressor to kick on for more than a few seconds, and when it dose it is making not normal noises.

Is my compressor history? Or can it be fixed? It dosen't seem to be leaking any oil, just squeeking when it tries to kick on. It will kick on every minute or so but only stay on for a few seconds.
What should my guages be at with 134a? could this be my problem?
Any advice on the subject would be greatly appreciated.
Thanks
Shawn