I had the A/C system rebuilt a few years ago (1990, 740 with R-12) and it worked fine for about 1 1/2 years. It stopped cooling but the compressor was cycling on and off very quickly. A friend had some R-12 and offerd to charge it up. When we put the guages on there was very little difference between the suction and discharge pressure. It has been quite a while since we did this but I think the pressure was around 40 PSI at idle?? The ambient temperature that day was about 95 degrees also. We tried to put some R-12 into the system but it would only take a small amount, probably because of the small pressure difference. I haven't messed with it in some months and am not sure ehat to do. I know I don't want to spend another $1500 bucks.

Any suggestions are greatly appreciated.