Don,

I do not mean this as a put-down, but judging from the questions you have asked, you are about to flirt with a possible disaster.

Without gauges and some knowledge of a refrigeration system, you will be much better off paying someone to tend to this for you. These things have been known to blow up in peoples' faces.

Hope this helps you make a prudent decision.

__________________
Ted
1979 240D
165,000 miles