Finish Thompson PFM/PFP/PFV Vapor Seal and Bearing Replacement - Manual (Page 8)

Insert outer tube over shaft assembly.
The outer tube will want to “hang up” on the
guide bearing.
Slide outer tube all the way to the head and tighten
(turn counterclockwise)
Reinstall the impeller housing cover
by turning counterclockwise
To install the impeller you will need to hold
the pumps coupling…