Service Manual

6
Inside the cartridge valve there is the valve spool,
the armature and the armature spring. The manu-
facturing tolerances are extremely close and great
care should be used when cleaning this type of
valve. Cartridge valves used in most Toro equip-
ment should not be disassembled. Figure 20 is for
illustrative purposes only. The best way to clean the
cartridge valve is to submerge the valve in clean
mineral sprits and use a probe to push the internal
spool in and out 20 to 30 times to flush out the
contamination. Mineral sprits does not affect the O-
ring material.
Understanding the basic hydraulic systems and
components can be of great value when trouble-
shooting and testing hydraulic equipment. Most hy-
draulic systems will be similar to one of these two
basic systems (Fig 22).
Figure 23 shows the actual hydraulic circuit for a
Greensmaster 3000. This circuit and components
are used to drive the unit in the No.1 traction posi-
tion. When the engine is started, the pump draws
oil from the reservoir through the suction lines. Oil
from the No.4 section of the pump passes through
the fitting in the No.4 spool valve into the valve.
The traction lever, when located in the No.1 posi-
tion, moves the spool so oil is directed to flow into
the No.5 metering valve section. When the traction
pedal is pushed forward oil flows out the lines at the
rear of the metering valve section to each motor to
drive the motors. Low pressure oil returns through
the valve and the main return line, through the filter
to the reservoir.
The more sophisticated a hydraulic system be-
comes, the greater the importance of separating
the system into individual circuits when diagnosing
a hydraulic problem.
Figure 20
Figure 21
Figure 22
Figure 23