I've never re-sealed a vacuum pump, but have replaced dozens.
As HookMeUp stated, leave the PS pump where it is. You don't really even need to remove the battery or intake. Get what PS mounting bolts you can from the top, and the rest from underneath. Same with the 2 vacuum pump mounting bolts.
Ditto the cleaning before you start. Try to wash the underside as well.
When you are ready to install the vacuum pump, make a note of the alignment groves in the vacuum pump and pre clock the PS pump before you slide it in (IIRC it is a keyed shaft). Make sure you don't nick the new seal and make sure the PS pump shaft is clean ad burr free.