A/C Question...not MB but shouldn't matter...
 

My friend is trying to repair the A/C on a late 90's Porsche Boxster. The car needed to have the aluminum lines which run under the body replaced because the tech at the porsche dealer decided to lift the car from them and crushed them during a routine maintenance job. My buddy discovered the A/C didn't work right after he picked it up and the dealer then said the lines were corroded and wanted $800 to replace them without ever acknowledging they crushed them...but that's another story.

So my friend buys the lines and replaces them. Upon evacuating and charging with the proper amount of refrigerant the pressures on both the low and high side taps skyrocket as soon as the compressor engages and the high pressure cutout switch activates and shuts down the compressor. Now, it is puzzling enough that the system worked prior to the tech causing the old refirgerant to leak out by crushing the lines, but what could cause both the high and low pressure taps to shoot up in pressure when the compressor kicks on? My first thought was it was overcharged, but they have evacuated and charged it twice with 30oz of R134a which is what is prescribed and the same thing happened both times.

Anyone with any ideas/suggestions?