Not trying to scare you, but there is a VERY remote possibility that the vacuum pump can shred the engine, but it has nothing to do with the seals and 1-way valves that you will replace when you rebuild the pump.

Once you get the pump off (get a long allen t-handle to do this), inside you will find a roller bearing that rides on a wavy-shaped cam in the front of the engine. This provides the reciprocating motion to drive the pump diaphragm.


If that bearing goes out, it could drop balls or bearing cage parts into the path of the timing chain, and I'll leave the rest to your imagination.

It's unlikely that this will happen since the bearing is smothered in oil at all times, but be SURE to check it for free rotation and no play before you button it up. And don't blow it dry and spin it with compressed air, either.

Otherwise, it's a pretty straightforward R & R--Let us know how it turns out!
Nate
'79 300D
'84 300D Turbo (pix to follow soon)
'85 F-250 6.9 Diesel
'96 Ford Crown Vic