Finish Thompson PFM/PFP/PFV Vapor Seal and Bearing Replacement - Manual (Page 7)

Carefully turn the shaft and head upside down and
press the bearing assembly into the head.
This should press in by hand rather easily.
S
pecial attention should be given not to
bend the shaft.
Using a lubricant (such as Vaseline) lubricate the
o-rings on the inner upper tube and center bearing.
Slide the upper inner tube up the shaft and press
the tube into the head.
You should feel the two o-rings snap into place.
Slide the lower inner tube up the shaft and press
onto the adjacent side of the center bearing.