The sheet supplied with the new Pierburg vacuum-pump I installedon my '84 TD mentioned cam wear. My cam had some visible wear marks but nothing I could catch with my fingernail. So I went with it. Four years and several thousand miles later, the new pump is still hanging in there.

On a slighly different note, there have been some vacuum-pump threads here that included mention of possible alternative vacuum pumps.
Last week, while foraging in the Virginia Beach Pick-N-Pull, I happened to wander over to the GM section. I spotted a belt-driven vacuum pump in an '81 Oldsmobile 98 Regency. The pump was mounted on a 5.0L Oldsmobile gas V8. No idea if these pumps are common or still availible, but I thought I'd mention it if anyone is looking for an alternative-pump research candidate.

Happy Motoring, Mark

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DrDKW