JLG X20JP - X600AJ Service Manual - Manual (Page 197)

SECTION 5 - HYDRAULICS
3121623 – JLG Lift – 5-19
EMPTYING OF THE CYLINDER
Vent Valve
Air inside the circuit has to be removed in order to avoid
vibration and irregular motion of the cylinder, vent valves
are apply to make this kind of operation.
Failure to remove air from the circuit can cause diesel
effect with consequent damage of the seals.
Be sure that there is no presence of air inside the cylinder
before it start working.
Purge screw
LOOSEN PURGE SCREW TO LET AIR ESCAPE TIGHTENING
TORQUE 8 N/M.