Lots of air in the system, very greatly reduced cooling capacity, and very high pressures.

A blockage at the expansion valve will give high head pressure (as will a blocked condensor, by the way --is the aux fan running, and is the condesor clear of crud?) and VERY low (as in vacuum) pressure on the low side.

If it was leaking freon out, it was leaking air in.

You need to do the following:

Check the condesor for buildup of crud between condesor and radiator, or just plain accumulation of slop preventing air flow.

Verify that the aux fan comes on (it must, at that pressure) -- check fuse if it doesn't, it's very likely cracked as mine was.

check to make sure the high pressure side is hot and the low pressure side is cold -- suction hose fitting should be condensing water out of the air, but no frost.

Chances are the how side isn't very cold, in which case I'd say you have way too much air in there. You need to vent it, fix the leaks (almost surely bad orings, replace them ALL, including the ones on the pipe manifold on the compressor, renew the oil, and replace the reciever/dryer. I'd do that only after you KNOW it will hold vac for at least an hour (you will need to pump overnight if it's been leaking a while).

Lots of work, but leakstop won't fix eroded o-rings. If you want to stay with R12, get it recovered if you can, otherwise you need to flush and replace the oil with PAG 46 oil and charge with R134a.

Been there, done that -- save yourself repeated work and do it right the first time.

PAG oil picks up water terribly, and withR134a water makes hydrofluoric acid -- you must change the reciever dryer EVERY time you open the system for any length of time.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!