Your response was very helpful, even a relief, and I thank you.

Could you please answer a couple of other questions at your convenience?:

1. Can you confirm that the capacity of the a/c system on the 420 SEL, '86 model, is 1.1 Kg = 2.425 pounds? In research, I also came across another source quoting the capacity at 2.9 pounds. I'm confused.

2. Could you please tell me what High & Low side pressure gauge readings I should see when the a/c system is topped off with R-12, at idle speed and 1,500 rpm?

Thank you for your valuable help.
William