You can try Ebay. I've seen a wide variety of manuals on there.
I'd probably go for the printed real MB manuals if you can find them,
as opposed to CD's. Both for convenience as well as I'm not sure
exactly what would be on CD's vs the genuine ones. If you're
planning on keeping the car, it's well worth the money.
With that vintage car, you're probably in for many hours of
investigation to get all those systems working again. You'll need a
Mighty-Vac or similar vacuum tester to use. You can find them at
auto parts stores or Ebay. And if the climate control system hasn't
worked in a long time, it's likely that there will be more wrong with
it than just the vacuum being disconnected. The climate control servo
and amp are notoriously failure prone.
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