Komatsu PC88MR-10 Shop Manual page 182

10 Structure and function
Control valve
Boom hydraulic drift prevention valve
Function
When the boom lever is not operated, this valve prevents the pressurized oil in the bottom side of the
boom cylinder from leaking through spool (1) to prevent hydraulic drift of the boom.
When boom RAISE operation is performed
When the boom RAISE operation is performed, poppet (2) is pushed up by the pressurized oil from the
control valve.
The pressurized oil from the control valve flows through the valve to the bottom side of the boom cylinder.
10-104
(PC88MR-L6C0-042-K-00-A)
PC88MR-10