vacuum pump dump? 89

[odieub]

This is for a friend. Has a vacuum pump setup from a 89 on a 4bt in a f150. And we could find an answer to this question. Where does the pancake style pumps dump the air. To the atmosphere or into the crankcase like the vein pumps . This is only if u have a leak in the vacuum air system, I know.

 

[joefarmer]

I've never seen anything but a vein-style vacuum pump. Care to post a pic? I'm curious how they look?

 

[jimbo486]

Atmosphere, I believe. The pushrods are sealed with O-rings so I can't see any way for it to dump into the crankcase. I could be mistaken though as I think the can in stamped "inlet".