I had the same problem on my '95 E320 cab- I thought it was power steering fluid.
Turns out it was coming from the weep hole in the water pump which drains via a drain tube onto the AC compressor and from there onto the floor.
Installed a new water pump and problem solved !

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1990 300CE-24 (Gone but not forgotten)
2002 SLK 32 AMG
2002 ML320 (Gone)
1995 E320 Cabriolet