Park sells a rebuild kit on their own website that's supposedly fcompatible with the PFP-5 or PFP-7.
And.. Park tool has some documentation.. Have you tried looking thru these various sources?

https://www.parktool.com/product/pro...tabbed-section
and
https://www.parktool.com/product/pum...or-pumps-1096z
and/or
https://www.parktool.com/blog/repair...r-pump-service