Front Of Hydraulic Oil Tank.
(1) Flushing Valve.
Flushing valve (1) is located on the front side of the hydraulic
tank. The valve has seven test ports for measuring pressures
of the propel, vibratory and charge systems and the scheduled
oil sampling test.
(14) Speed selector switch. (15) Propel lever.
The operator controls the propel system using speed selector
switch (14) and propel lever (15). When the operator moves
the switch from Low Range to High range, solenoid on parking
brake and speed shift valve (8) sends the unfiltered charge oil
to rear axle and drum drive motor displacement port. This
changes the motor displacement from maximum displacement
to minimum displacement resulting in higher speed operation.
With the switch in the Low Range position, the displacement
ports for the two motors are open to case drain. The biased
motor is maximum displacement. By moving the propel lever
forward or backward, the operator sets the displacement of the
propel pump. This determines the direction and speed of the
Right Side Under Platform.
(16) Charge filter.
Charge filter (16) is located on the right side of the machine
under the platform. This is a 13 micron filter, that has a
manual indicator for bypass. If the filter becomes plugged, a
pressure drop is created. When the pressure drop reaches
350 kPa (50 psi), the filter bypass valve opens and oil flows
through the valve to the spring loaded check valve. The check
valve is part of parking brake and speed shift valve (8). When
the pressure reaches 1220 kPa (175 psi) in the passage
between the bypass and check valves, the check valve opens
and oil flows to the thermal bypass valve and on to the oil
cooler if needed. At the same time, if the charge pressure
drops below 1220 kPa (175 psi) after the filter, then a warning
light and horn will sound off. The check valve prevents the
brake pressure from dropping below 1550 kPa (225 psi).
A pressure drop of 172 kPa (25 psi) across the
filter shows red on the visual bypass indicator
which means the hydraulic oil filter should be