check valve and flows from the work port to the rod end ports of both carriage tilt cylinders. The load compensating check
valve operation is the same as described in the MLRS attachment system. Oil pressure unseats the ball check in the
counterbalance valve on the rod end and pushes the cylinder piston into each cylinder. Oil in the head end of the cylinder
flows from the head end port and back to the MLRS control valve. The cylinder retracts which raises the fork tips. Oil from
the tilt cylinders is directed to the MLRS control valve return circuit and back to the hydraulic reservoir through the
If the electric joystick is moved to the right, the second from the top left solenoid is energized. The oil flow through the
second section is similar to the fork tips raise function but the oil flow to the tilt cylinders is reversed. Oil flows to the head
end of the tilt cylinders and pilots open the counterbalance on the rod end of the cylinders. Oil is allowed to flow from the
rod end and back to the return circuit of the MLRS valve. The cylinders extend and lower the fork tips.
A port relief valve set at 3000 psi (20685 kPa) is connected to the rod end of the tilt cylinders. The relief valve protects the
hydraulic lines from bursting when shocks or spikes are encountered on the rod side of the cylinder.
The fork tips lower port relief valve is connected to the head end of the cylinders. The relief valve is set at 725 psi (5064
kPa) to limit any external upward force on the forks.
g. Fork Sideshift System. The fork sideshift function, as with the previous two functions, is controlled by the electric
joystick and the MLRS control valve. Hydraulic oil from the piston pump flows through the control valve as in the other two
MLRS systems. The third section of the MLRS valve controls the left fork (right cylinder) and the bottom (fourth) section
controls the right fork (left cylinder).
Push the button on top of the electric joystick and move the joystick to the left and the third from the top right solenoid is
energized. The solenoid allows pilot oil to flow through the solenoid and push the spool in the third section towards the left
of the machine. System oil flows through the third section, pilots open a load compensating check valve and allows oil to
flow from the work port to the head end port of right cylinder which moves the left fork to the left. Oil in the rod end of the
cylinder flows back to the return circuit of the MLRS control valve.
If the button is held and the electric joystick is moved to the right, the third from the top left solenoid is energized. The oil
flow through the third section of the MLRS valve is similar to the above left fork motion but the flow to the cylinder is
reversed. Oil pressure is sent to the rod end port of the right cylinder which retracts the cylinder and moves the left fork t o
The above description of hydraulic function for the left fork can also be applied to the right fork. The button is held down
while the electric joystick is moved front to rear to control the right fork position.