Polaris 2007 Sportsman 500 EF Service Manual page 256

FINAL DRIVE
4. Coat new piston and o-rings with a moderate amount of
white lithium grease or assembly lube. Coat the edges of the
piston cavities. Install the inner and outer piston o-rings.
5. Place the piston in the piston cavity, aligning the pins with
the pin bosses. Using the casting and piston marks as a
guide as shown will aid pin alignment.
7.28
Outer
Inner
6. Place ADC Piston Tool PA-48542 on top of the piston and
verify alignment of the sight hole (circled) and piston mark
with the casting marks. Support the case and press the
piston down evenly. The piston is fully seated and located
in the pin bosses when the piston surface is just below the
cavity edge.
Tool PA-48542
7. Repeat procedure for the other gearcase half.
NOTE: Verify that the o-rings are seated properly
and that no o-ring shavings exist outside of the
piston area, which is an indication of damage during
installation.