It sounds like you wouold be doing it right.
Track down the leaks and repair them. The parts probably don't cost much, see if you can find the part numbers or go through the fastlane...
'92 300CE - Sold
2004 C240 - C7 Wheels
2015 ML350 - P1, Pano, Ash poplar wood, Sport Dinamica interior, Running Boards Keyless go.