I believe that MB has a special tool, but I am able to remove by hand. It is sealed with an o-ring, so it only needs to be snugged. If yours is very tight you could use a small strap wrench.

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-Wayne

1994 E320 Coupe (120k)
1990 300SL (BBS,RENNtech adds)
1988 260E Sedan (180k)