When you undo the long bolt that holds the filter up, keep it pressed into the assembly and lower the whole thing into your oil recepticle as an assembly then empty the oil out, being careful not to lose bits.
DON'T merrily unscrew the bolt out and withdraw it, unless you want all the oil to pour out through the hole that it left.
Remember assembly is the reverse of dissassembly and to put the spring and plate back (as Alex mentioned).
Do it hot, but remember hot oil scalds!
I've never replaced the oil seal on the filter housing (I'm inherantly lazy)and I've never had a leak.
No need to anneal anything here as they're rubber seals!
Some people refil the housing before fitting with fresh oil to prime the system.
Take the point with SAABs though, I use a new washer/anneal every time, or they leak terribly and it's an odd size bolt. Nothing seems to fit. Oh those Swedes. such a sense of humour

At least I can say I have a Koenniggse now!
Andrew
Maggie, 1969, 4 door, Almond Green.
And Project "Traveller"...
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