AC leak troubleshooting help

[erubin]

Here is a general question i have for help identifying an AC leak in R12 and R134a systems.

Occasionaly I have a non working AC system because the refrigerant has leaked out. I need away of finding the leak. I have a couple of AC tools including:
UV leak detector light
vacuum pump built from a refrigerator compressor
manifold gages (good for R12 and R134a)
cans of R134a with UV tracer

I do not have a recovery system nor a refrigerant sniffer. They are too expensive for my budget. I don't plan on venting R12 into the atmosphere.

How do I locate the source of a leak with the tools that i have? Would charging with R134a and forcing the compressor on (short the pressure switch) be the way to go using the UV light? What about R12 systems, could I load R134a in them simply for locating the leak. Of course the R134a would be removed after testing.

[erubin]

To wrap up and share what I've learned since I first posted this...many systems already have UV tracer in them so it is worth snooping around with a UV light in the dark. Also the easiest thing to look for is signs of oil leaks from the AC system. They often tell you were the leak is. The tricky one is the evaporator cause it's buried in there. look at the evaporator drains under the car for hints. Also it is worth noting if that particular make and model have historical evap leak problems or not. a knowledgeable tech specialising in that car or in AC systems could shed light on that.