1994 Other Mercedes Benz Models compressor stops

Air Conditioning problem
1994 Other Mercedes Benz Models 6 cyl Two Wheel Drive Automatic 157K miles

Hello, I have a 199 E320, 6cyl, Gas,
The problem is that the compressor stop after a minute or less, I added an oil shot, then leak detector/sealer no luck, but here is the odd thing, with the low side pressure down to about 15lbs, the compressor runs, but of course no cold air, if I add 134a eventually the compressor will start to squeak/squeal and then shut back off. If I start the car with the A/C switch on the compressor will run but I have to race the engine till the squealing stops (about 35K rpm) then I can add the 134a till the pressure is correct and no air bubbles but as soon as I let off the Gas the compressor will give a quick squeal and then shut off.

any help would be appreciated.

Thanks!