This diagram is for the later 606 but I believe the filter assembly is the same as yours.



I'm pretty sure there's only 2 O-rings on the pre-filter - the one on the inlet line #32 and the one around the larger part of the filter - #29.

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250