Here's my test setup. An old plastic vacuum line connecting the 2 vac pumps.



The wire clamped to the pump is a gauge to indicate if the cam follower moved or not. 22" Hg was insufficient to move it.

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked