Komatsu PC88MR-10 Shop Manual page 237

1. When there is a damage in the piping (A) between the control valve and the work equipment cylinder, the
pressurized oil of chamber (a) leaks through the damaged part to the outside, but it is supplied from
chamber (b).
2. The pressurized oil flows through the opening (C) of spool (1), and it prevents the work equipment from
sudden lowering.
PC88MR-10
10 Structure and function
Anti-drop valve for arm
10-159