About a month ago, I received a suggestion from 123 300D Driver (Gary) that pointed me towards a defective vacuum bleed valve that is tied to the ignition switch.

Following his advice, it looks like his tip was correct.

Next question- The Haynes manual I have doesn't show it, and my M-B manuals do not either (incomplete set) --

Can anyone advise where the vacuum bleed valve for the ignition switch is, and is removal of the igntion switch necessary?

Thanks to all,
Nate Stanley
'79 300D
'85 F-250 6.9L Diesel