Aiming should be roughly in a W pattern, hitting the glass, I believe, about 2/3 the way up, which will hit at about halfway up at speed on the highway.

I had 3/4 completely corroded shut and was able to carefully drill them out with a super fine bit and a small hand drill. Bit cost me less than a dollar at local HW store.

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David
1986 300E Anthracite + ECodes + MB Mileage Award