vacuum pump lube or what is it

Hello to all
Had to replace the alternator on the 1992 L3 engine.
There was an blackish oil in the vacuum lines. Not a lot, just a few drops came out. Was it a lube for the pump or was it

an unknown problem to be explored.

If lube, what to replace it with? A bit of air tool oil??

Thanking all

Stephen

No lube required, probably sucked in if the pump spins freely nothing to worry about.

So long as the vacuum pump was replaced with the alternator then there is no issue.
The black oil is engine oil that has got into the vacuum system from leaky seals in the vacuum pump.
(The pump is lubricated by engine oil that is delivered under pressure from the engine)
you can (if you want) clean out all the lines but it is a tedious job that provides no benefit.
Just clean the hose ends where the lines plug into fittings and all will be good.

I hope this helps.