I saw this yesterday and was hoping you would get some gen8 specific comment before I chime in. Didn't happen... so: In my gen9 the setup is similar. Seal inside by the camshaft, gasket between pump and camshaft cover. When I changed mine I used a Kent Moore j-45866. I don't know if that is the same size for your gen8 or if there is a specific tool. You take out the old seal then use that tool to perfectly pop in the new seal. You should be prepared with a new gasket for the back of the vacuum pump. Probably cheaper to just buy the pump as it comes with the gasket and is only a few bucks more.