If you believe info found in the a/c theory manuals and what you can read at the various WEB yack sites, R-12 high side pressure as a "rule of thumb" is approx. 2.5 times the ambient temp reading taken about a ft. in front of the cars condensor. I realize there are variations in the different systems out there.

If the reading taken is 90F, multiply 90 x 2.5 = 225 lbs.

You did mention R134A and the pressure in that refrigerant is different than R-12, but in your case, I believe this formula has value. It indicates that you are way deficient on the high side.

I would take a static reading of your low side and report that value here so that a knowledgeable person could comment. You take this reading with the car & a/c turned off. Kind of like checking pressure in your tires. I've always believed that a simple static reading is a good place to start, especially if one suspects a low charge condition.

My 2 cents.

__________________
Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"