I have a cavalier C7 machine that has a 1/3hp compressor on it.  It had a hole in the condenser and I found one that would fit it and it was the exact same size.  I pulled a vacuum on it for 2 hrs.  The tag on the box says it takes 10.8 ounces of R12.  I put a full 12ounce can in it.  My static pressure is 48lbs.  When I plug it in the machine pulls the suction pressure down to 2lbs after about 2 minutes.  I thought maybe I have a blockage, but when I unplug the machine the suction rises immedaitely.  What should my static pressure across my system be?  Am I low on freon even if the tag says 10.8 ounces?

I left the hoses on over the x-mass weekend and did not have one of them tight and my r-12 leaked out.  I did not have anymore of the liquid gold so I put freeze-12 in it instead.  The tag is right.  I found a post from Eric and found what my pressure should be for the temp of the box.  Working fine now.