Gen 1 Q45 AC charging adaptor question

[Highway Q45]

The AC on the Q has been working great for 3 years since having all the O-rings, drier, etc replaced and dealer serviced. It appears that the coolant level has finally dropped enough to trigger the low-pressure cut-off switch. I tried to top it off with R-12 today but ran into a problem. Most of my other cars (German) use R-12 also and I have no problem connecting the manifold hoses without losing coolant before topping off. On the Q the LP side is fine but the HP side wants to release gas long before the threads for the hose engage. The fittings on the hoses have the blade type depressor so that's not the problem. The shop manual shows a valved Infiniti adapter to be used between the LP and HP fittings and manifold hoses. My question is: Do others have this same problem with their R-12 manifold set or are the OE adapter valves absolutely required for a simple top off? The system was leak tested and held just fine. I consider the leakage over 3 years acceptable as there is no such thing as a leak free system. The reason I do it myself is that shops won't just top off anymore, they have to evacuate the system, check for leaks, tell me they couldn't find any and then charge you for extra R-12 while lying about how much they recovered. That usually amounts to about $400-500 when they are done. The last repairs 3 years ago cost over $1100. I have enough R-12 to last me and 3 older cars for another 10 years so I'm just trying a top-off.

Any opinions welcome other than I'm melting the polar icecaps.

[Q45tech]

The $15,000 recovery machine has the correct hoses that clip on to the correct adapters...........................leaking o rings in the adapters is common and you must replace them every year.

Proper machines print out the exact amount of recovered R12 so there is never a question as to amount recovered.

Paying $900 for 30 lbs and marking in up 100% to $60 per pound is current industry average..........this $75 [for 2.5 pounds] is what pays for the machine and tools....UV light/sniffer leakdetection.......and the $2,000 in annual maintenance and machine repair.

It takes 100 - R12 customers per year to breakeven, why fewer and fewer shops are dealing with R12 now..............not worth the hassle.

Secure the correct tools and adapters.

[Highway Q45]

Thanks Dennis- Will the adaptor(s) still connect to a standard R-12 hose set or did Nissan make special hoses to mess things up even further? These are the first R-12 fittings I've seen with a quick-coupling ridge at the base. Any idea how much those adaptor couplings run?