What are those rare, elusive parts that you cannot find at any cost?

I'll start: 450SEL 6.9 shock absorber rebuild kits! Gone, and gone forever!

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[GONE] - 1995 Mercedes E300 Diesel - 130k miles - Smoke Silver (702) over Mushroom leather (265) - Bladder blasting, coast-to-coast work machine.

the S shaped vac hoses for the little valves on the valve cover

W123 US spec headlight doors. Once plentiful and cheap now gone.

AMG vintage hockey puck center caps. Same story

Head gaskets for pre-merger AMG engines. True, Indiana-Jones-breaking-into-temple grade of unobtanium.

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[GONE] - 1995 Mercedes E300 Diesel - 130k miles - Smoke Silver (702) over Mushroom leather (265) - Bladder blasting, coast-to-coast work machine.

W123 dashboards... how many times have I heard people wishing they could buy them new?

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[GONE] - 1995 Mercedes E300 Diesel - 130k miles - Smoke Silver (702) over Mushroom leather (265) - Bladder blasting, coast-to-coast work machine.

Just half as many times as we W114 owners have said the same thing!

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“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

Crack-free w116 dashboards, if you can even find a w116 being parted out.

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Only diesels in this driveway.
2005 E320 CDI 243k Black/Black
2008 Chevy 3500HD Duramax 340k
2004 Chevy 2500HD Duramax 220k

Lots of Corrado G60 parts...seatbelts come to mind off the top of my head....

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2009 Kia Sedona
2009 Honda Odyssey EX-L
12006 Jetta Pumpe Duse
(insert Mercedes here)

Husband, Father, sometimes friend =)

Service manuals for just about every model.

Blue door cards for a W201 w/power seats & windows.

Wanted to mention the W123 dashboards. I was told the press to mold them broke and they never fixed or replaced it. Was also told it was the only original Mercedes part not available anymore, that was 15 years ago.

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1979 Black on Black, 300CD (sold), 1990 Black 300SE, Silver 1989 Volvo 780, 1988 300CE (vanished by the hands of a girlfriend), 1992 300CE (Rescue).

There is one at the junk yard in Sun Valley at the moment, but you don't see them that much anymore. W123's are getting less as well, lots of W124 and some W140's on the other hand.

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1979 Black on Black, 300CD (sold), 1990 Black 300SE, Silver 1989 Volvo 780, 1988 300CE (vanished by the hands of a girlfriend), 1992 300CE (Rescue).