Gradall G-550C Operation And Maintenance Manual page 3

G-660C & G-880C GRADALL (Crawler)
UPPERSTRUCTURE INFORMATION
The crawler drive system is powered using hydraulic
oil from the Gradall upperstructure. Each track is
supplied with oil of the following GPM.:
G-660C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 GPM
G-880C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 GPM
The crawler drive circuits in the upperstructure
control valve banks are protected by relief valves as
follow:
G-660C:
Main relief valves . . . . . . . . . . . . . . . . . . . . . . . .2500 psi
Circuit relief valves . . . . . . . . . . . . . . . . . . . . . . 2200 psi
G-880C:
Main relief valve . . . . . . . . . . . . . . . . . . . . . . . . 2500 psi
Circuit relief valves . . . . . . . . . . . . . . . . . . . . . . 2400 psi
BOOM ASSIST FOR CRAWLER TRAVEL
A new feature that has been added to the hydraulic
circuitry, is that you can now use the boom in-out
actions to assist you to either push or pull when
traveling in tough conditions.
This is accomplished by adding an additional valve
behind the swing, tilt and tool valve sections. When
traveling in any direction, this valve is actuated and
the oil from the swing, tilt and tool valve (30 gpm for
660, 37 gpm for 880) is routed to the boom control
valve for use.
INTRODUCTION
This portion of the service manual is supplied to show
the portion of the Gradall excavator that relates to the
crawler undercarriage.
For information regarding the Gradall upperstructure
functions, refer to the manual portions covering it,
but disregard the sections related to the remote
control carrier. (Rubber tired).
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OPERATION & MAINTENANCE