JLG E300 Service Manual - Manual (Page 168)

SECTION 5 - HYDRAULICS
5-26 – JLG Lift – 3121253
6. Continue activating the platform rotate switch
momentarily until the assistant sees a clear, uniform
stream of hydraulic fluid flowing from the test hose
into the hydraulic reservoir.
NOTE: An audible change in the tone of the gear pump
should be heard when the air is purged from the
gear pump.
7. Disconnect the pressure test hose from the MP port
on the Main Control Valve.
8. Remove the hose end from the hydraulic reservoir’s
breather/filler port.
9. Install the breather/filler cap.