Agilent IDP-7 Not Pressurizing after Tip Seal Change

So after a tip seal change on my Agilent IDP-7 scroll pump I could not reach pressure aka there was a leak somewhere. None of the guided maintenance tutorial videos or written instructions mention one EXTREMELY important element.

There is a small O-ring on the orbiting scroll that easily pops off. While doing clean up at my work station I found the missing O-ring which helped guide me to finding the leak. My tip seal replacement kit from Global Vacuum came with the housing O-Ring, Tip seals, and this little O-Ring.

After greasing and installing the new O-ring at this location I was able to reach target pressure in less than 10min.