Precor C842i - Manual (Page 70)

C846i/C842i Recumbent Cycle Assembly Guide 4
Rest the seat pad against the seat frame posts. Insert the four
buttonhead screws (C) and finger tighten.
CAUTION: It is critical that you hand thread the four
buttonhead screws before alternately tightening them
with the hex key (E). The nut inserts on the back of the
seat pad can be easily stripped by improper assembly,
which is not covered by the Precor Limited Warranty.
When the four buttonhead screws (C) are properly threaded,
alternately wrench tighten each screw using the hex key (E).
Sit on the seat to adjust it. Pull up on the seat adjustment handle
and use your legs to slide the seat along the center post.
Note: If the seat rocks from side to side, you will need to realign
the center wheel that runs inside the center post. Refer to the
instructions in the Product Owner’s Manual.