Just did my filer on a 91 560 SEL. I had to re-use my rings. they were copper and needed a good tightening to prevent leaking.

On the other end I used some teflon tape on the threads. I had an issue though. The filter came with a fitting that I had to remove because the one on the fuel line on the driver's side was fused/rusted onto the fitting. So when I removed the filter, that fitting stayed.

So I removed the bolt-but thingy on the passenger side with the TWO copper rings. I think unthreaded the filter from the line on the driver side. Not that I did it, I am sure next time will take a lot less than an hour!

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1991 560 SEL / 185k miles
1992 750il / 17k miles - project car