On A 1987 Mercedes 260e A/c What Hoses Is The High And Low Pressure Side?

Some cars have different color hoses on the ac the high side is where the refrigerant goes in a can of free on usually will tell you which is the high side

The low or suction side will be the largest of the two hoses/lines. Usually the connection is closer to the interior of the car, and the high side is closer to the front of the car. This is true on almost any A/C system, car or home, foreign or domestic

I am not too familiar w/ german cars, but I would guess the hose that has the bubble glass would be your high pressure hose.