(I would get these before you start.) If you central bolt has a metal washer copper or aluminum you will need a new one and a new "O" ring for the central bolt.
Some central bolts do not have this washer and some central bolts have 2 "O" rings.
I changed my primary filter thinking I could do it without changing the "O" ring and It leaked. I was able to find a new one that worked from a "O" ring assortment that I bought long ago from Harbor Freight.

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84 300D, 82 Volvo 244Gl Diesel