<VV> AC Leak Question

[LanningWB at aol.com]

I have a '66 Corvair with factory R-12 system that has leaked down and I  
want to find the leak.  A rebuilt compressor with a new seal was installed  last 
year.  The system was recharged then and seemed to hold the  charge over the 
summer (at least it cooled all summer).  Over the winter  the freon leaked out.
 
I pressurized the system with nitrogen to 60 psi.  In 24 hours it  leaked 
down to about 35 psi.  I tried to find a leak using soap with  no luck, however I 
have not pulled the pulley to check the seal.
 
Does anyone know anything about the flourescent dye that AC shops use with  a 
black light to find leaks?  Does it work good?  If so, where can I  get it?  
Or is there a better method to find the leak?  BTW, I have an  MVAC license so 
I am "legal" to work on the system.  
 
Tx, Wade