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| Illustration 1 | g01182874 |
Partial hydraulic schematic (1) Boom cylinder (2) Main control valve (3) Boom control valve (4) Pilot control valve (Boom and Bucket) (5) Oil line for boom lower operation (6) Oil line for boom raise operation (7) Main pump (8) Hydraulic line (9) Pilot manifold | |
Note: The joystick controls for the boom hydraulic system can be set to a Standard pattern or an Alternate pattern (if equipped). The hydraulic activation control must be activated in order for the pilot valves (joysticks) to function.
In the Standard pattern, the boom hydraulic system is controlled by the right pilot valve (joystick). When the right pilot valve (joystick) is moved forward, the boom will lower. When the right pilot valve (joystick) is moved backward, the boom will raise. When the pilot valve (joystick) is released from either position, the pilot valve (joystick) will return to the HOLD position.
Reference: Refer to the Operation and Maintenance Manual, "Joystick Controls" for more information on the operation of the pilot valve (joysticks).
Boom Lower
When the pilot valve (joystick) is moved forward, pilot oil (5) shifts the spool of boom control valve downward. Supply oil is routed from the pump (7) to the main control valve (2). The pump receives oil from the hydraulic tank through the hydraulic line (8). The supply oil flows to the rod end of the boom cylinder (1) through the boom control valve (3). This causes the cylinder rod to retract. The retracting of the cylinder rod causes the boom to lower.
Boom Raise
When the pilot valve (joystick) is moved backward, pilot oil (6) shifts the spool of boom control valve (3) downward. Oil is routed from the pump (7) to the main control valve (2). The pump receives oil from the hydraulic tank through the hydraulic line (8). The supply oil flows to the head end of the boom cylinder (1) through boom control valve (3). This causes the cylinder rod to extend. The extending of the cylinder rod causes the boom to raise.