Well, what do you FK-ing know. Look what I discovered when trying to trouble shoot my steering issue. I must have jinxed myself looking at this thread.
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It appears the primary leak points for the vacuum pump can be either between the pump and the oil pan/block OR from the front cover of the pump itself. The pump is p/n LR048796, although this may have been superceded to a new number.
With a new pump at ~$400 for OE, or ~$250 for OEM Pierburg, I'm curious what the likelihood is the leak is from the O-ring on the back of the pump. This O-ring is available separately (p/n LR012685, ~$17 MSRP). The FSM seems to indicate the oil pan should be drained before removing the pump. The stamped-steel front cover of the pump may have another O-ring seal but that isn't sold separately, and I don't know what the pump looks like with the cover removed - couldn't find anything on the interwebs.
I'd be a bit annoyed if I replaced the O-ring on the back only to find it was leaking from the front cover.
