GUARD 9V8122 - Caterpillar

Illustration 1 g02988477
Schematic of the pilot hydraulic system (with the optional auxiliary pilot hydraulic system) (1) Pilot oil return (2) Line to lift spool of main control valve (3) Vent line from main control valve (4) Pilot oil return (5) Lift arm positioner valve (6) Float sequence valve (7) Line and orifice (8) Line to auxiliary spool of the main control valve (if equipped) (9) Line to tilt spool of main control valve (10) Line to auxiliary spool of the main control valve (if equipped) (11) Line to tilt spool of main control valve (12) Pilot diverter solenoid valve (if equipped) (13) Pilot diverter solenoid valve (if equipped) (14) Line to lift spool of main control valve (15) Lower valve stem (16) Raise valve stem (17) Dump valve stem (18) Tilt back valve stem (19) Pilot control valve (20) Pilot oil supply (21) Pilot oil returnThe pilot control valve (19) is operated manually by the operator. The pilot control valve sends low-pressure oil to operate the lift spool and the tilt spool in the main control valve.The lift spool and the tilt spool control the operation of the lift cylinders and the tilt cylinder. Oil lines (2) , (9) , (11) and (14) connect the output of the pilot control valve to the pilot inlets for the lift spool and the tilt spool in the main control valve.
Illustration 2 g03803645
(22) Switch (23) Joystick control leverPilot control valve (19) uses only one control lever (joystick type) to control the operations of both the lift function and the tilt function. Joystick control lever (23) is connected to a pivot plate that contacts the four rods for raise, lower, dump, and tilt back positions.When joystick control lever (23) is moved to a position, oil flows from the pilot control valve to the main control valve. The spool in the main control valve moves. Movement of the spool opens the passage for implement oil flow to the lift cylinders or the tilt cylinder.The pilot control valve section for tilt control has three positions, TILT BACK, HOLD and DUMP. The pilot control valve section for lift control has four positions, RAISE, HOLD, LOWER and FLOAT. The oil cannot flow through pilot control valve (19) when in the HOLD position because the valve is a closed center valve.
Illustration 3 g03334497
Partial view of the pilot solenoid diverter valve in the articulation hitch
Illustration 4 g03334500
Partial view of the pilot solenoid diverter valve in the articulation hitch (12) Pilot diverter solenoid valve (13) Pilot diverter solenoid valveNote: The optional auxiliary pilot hydraulic system controls the ejector bucket.When auxiliary pilot hydraulic system is activated, the DUMP position changes to EJECT position also the TILT BACK position changes to RETRACT position.Pilot diverter solenoid valves (12) and (13) are additional components in the optional auxiliary pilot hydraulic system.To activate the auxiliary pilot hydraulic system, press and hold switch (22) while joystick control lever (23) is moved to the EJECT or RETRACT positions. Switch (22) activates pilot diverter solenoid valves and