Well, the dealer had to replace the vacuum pump diaphragm on my 78 300D today. -Under warranty- I noticed blue smoke on start up
and 1 qt oil consumed in 1,000 mi.

About 6 months ago the top end was rebuilt, it also got a new water pump and vacuum pump diaphragm. The dealer said if this one fails in the next 6 months we may have to pull the pump to find out what's going on.

Are there any ideas as to what could be happening.
Maybe it was improperly installed?

Have a new vacuum pump installed. I haven't seen people installing diaphrams for years.

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Benzmac:
Donnie Drummonds
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

Donnie,
Thanks for the info,
Is changing the vacuum pump DYI job? I am fairly mechanically inclined.

Thanks,
Matthew

It's not too bad, more a pain in the butt, 'cause you have to get all kind of stuff out of the way so you can get to the darn thing. There are six allen bolts holding it on. Be sure to clean them out, so that your tool goes in all the way, and you don't round it out. A 3/8 socket won't work because the head is too fat ( the part that the ratchet goes in to), so you'll need to get some long allen wrenches.
From what I remember, you have to take off the main vacuum line, loosen the p/s belt, the a/c belt, take off the top of the fan shroud, and the fan itself. This ought to give you an idea as to how long it'll take you. Good luck, and don't be in a hurry.
-Larry

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03/83 300D 184k
07/73 280 160k