Hi,
Does the leak behind the cover appear to be engine oil? A vacuum pump wouldn't cause this to happen.
As far as replacing the valve cover gaskets (cylinder head cover gaskets) I attached the directions below. Note: The first four pics are related to the left side and the last pics are the right side.
The directions are vague and provide preliminary steps prior to the covers. I'm not sure what you are comfortable with, but if there is something specific you need in the list, let me know and I'll get it for you.
Let me know if this helps or if you have other questions.
Take care,
Joe
See pics below.
Images (Click to make bigger)
Monday, April 10th, 2023 AT 9:13 PM