I suggest that oil in the part of the vacuum pump which is open to the cranckcase is normal, oil in the part of the vacuum pump which handles air (vacuum) is not OK.
This generally indicates that a diaphragm has torn. It would be best to replace the diaphragm while you have the VP off.

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Tony from West Oz.
Fatmobile 3 84 300D 295kkm Silver grey/Blue int. 2 tank WVO - Recipient of TurboDesel engine.
Josephine '82 300D 390kkm White/Palamino int.
Elizabeth '81 280E, sporting a '79 300D engine.
Lucille '87 W124 300D non-turbo 6 cylinder OM603, Pearl Grey with light grey interior


Various parts cars including 280E, 230C & 300D in various states of disassembly.