The eBay product is specifically designed for power brake boosters that "consume vacuum" only when the brakes are actually used, meaning not very often for most folks who don't ride their brakes. Our diesels, however, use vacuum for all sorts of things and the vacuum pump is continuously active. All you have to do is have a vacuum gauge on one of the lines and push on the throttle or operate an ACC button or door lock to see it in action. It would be interesting to put a flow gauge in series with the main vacuum line to measure the amount of air that the vacuum pump has to pull out of the various vacuum-using components.

W124 and W126 and W210 (and other models?) have an electric vacuum/pressure pump for the door locks and pneumatic seats; those pumps run only when the locks are actuated. The W123 uses its engine vacuum pump for everything.

Maybe it's not as bad as I am thinking but it definitely is a lot more than just occasional power brake operation. That's why I suspect that the electric vacuum pump offered by the eBay seller is not rated for continuous duty.

OTOH, I would like someone other than me to try one and see what happens. I would be happy to be proved wrong, just not on one of my cars, please.

Jeremy

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970