Operation Manual
68
XR5519
Boom Emergency Lower Down Valve
Both of the lift and extend cylinders are equipped with a
needle valve which allows the cylinder to retract without the
direct assist of the machine’s hydraulic power. This feature is
intended to be used only in the event of total loss of engine or
hydraulic pump failure with an elevated boom.
In any event, the vehicle should be secured until the situation
has been properly evaluated. Secure the vehicle and area by
following the procedures below:
1. Clear the area around the vehicle of all personnel.
2. Place the shift lever in NEUTRAL and engage the parking
brake switch to the ON position.
3. Section off a large area under the boom with tape to
restrict any personnel from entering this potentially
dangerous area.
4. If the load is in a position where it can be removed safely,
completely remove the load from the carriage and/or
attachment. Otherwise leave the load in place.
5. Remove boom access cover on back of boom.
Fig 94. Boom Access Cover
Fig 95. Extend Cylinder Lower Down Valve
Warning
Keep fingers and feet away from moving
parts or pinch points to prevent pinching or
crushing. Failure to do so can result in death
or serious injury.
Fig 96. Extend/Retract Section of Proportional Valve
6. Locate needle valve on extend cylinder. Loosen nut on
valve, then loosen valve with hex wrench.
7. Thread a 125mm long M8-1.25 capscrew into the manual
operator of the extend/retract section on the proportional
control valve (second section from boom side, on top of
the valve) and use it to manually operate the valve to
retract the boom.
8. When boom is fully retracted, tighten valve with hex
wrench, then tighten nut to secure valve.
9. Locate needle valve on lift cylinder (under the boom).
10. Loosen nut on valve, then loosen valve with hex wrench.
