Brother of The Benz, joe 1
My W124030, converted to R-134A and off charging by 20% cools fine and doesn't blow any switches.
My capacity is 2.2 lbs of R-12 or 1.76 lbs of R-134A.
In filling from empty, this requires 2.34 cans at 12 oz/can total of 28 oz.
Charging only using 2 cans plus the 4 oz included in the oil charge if used totals at 28 oz.
If your system had any of the super additives put in, then you may be overcharge by the amount of R-134A included in each option.
joe1, you did right by reducing the amount of gas, but I think you went to the extreme.
Try adding one more 12 oz. can.
You Do have the low side pressure gauge don't you?
If NO, help yourself and get one.
Walmart and K-Mart have them.
As to handling R-134A in the heat in Houston, 98+ degree days and no problems.
If you were overcharged, then the condenser was super hot and that heat is passed on to the rediator.
Your A/C isn't keeping up with the weather it's just blowing cooled air in your face and on your hands.
The rections of all cars A/C in excellent condition and properly filled are the same.
Same high and low pressures; for these are what the system is designed for.
There is no reason to reccomend reducing the capacity to 1 lb.
For by doing this you have a dangeriously low liquid level in the evaporator and a reduced amount of oil in circulation that is required by the compresser.
To gaurantee oil return through the low pressure hose, the oil must boil over the evaporator top tube, and at your level it can't.
My Benz when in traffic indicates between 80 & 90 on the dash indicater. It may indicate 100 on one of those oven type days or;
While stopped in traffic,I slip the transmission to Nuetral and increase the engine speed to 1500 rpm. This increased air flow helps emensly.
Happy Trails Beep Beep from The Spiderman in Houston!!!