Toro Greensmaster 3120 Service Manual page 148

Cartridge Valves
Hydraulic System: Service and Repairs
Note: For solenoid style cartridge valve coil testing information; refer to
Solenoid Valve Coil (page
1. Park the machine on a level surface. Lower the cutting units, stop the engine,
engage the parking brake and remove the key from the ignition switch.
2. Read and adhere to the information provided in
Removing and Installing the Hydraulic System Components (page
3. Ensure that the mower manifold is clean before you remove the cartridge
valve from the manifold.
4. Remove the cartridge valve:
A. For solenoid style valves, remove the nut that secures the solenoid coil to
the cartridge valve. Carefully slide the coil off the valve.
Carefully handle the cartridge valve. Slight bending or distortion
of the stem tube can cause binding and malfunction. When
removing the cartridge valve from the manifold, ensure that the
deep well socket fully engages the valve base.
B. Use a deep socket wrench to remove the cartridge valve from the
manifold.
5. Record the correct location of the O-rings, the sealing rings, and the back-up
rings. Remove and discard the seal kit from the cartridge valve.
6. Visually inspect the manifold port and the cartridge valve:
A. Check for damaged threads on the cartridge valve and in the manifold
block.
B. If valve sealing surfaces appear pitted or damaged, the hydraulic system
may be overheating or there may be water in the system.
C. Contamination may cause valves to stick or hang up. Contamination
can become lodged in small valve orifices or seal areas causing valve
malfunction.
Use eye protection such as goggles when using compressed air.
Note: Particles as fine as talcum powder can affect the operation of high
pressure hydraulic valves.
7. Clean the cartridge valve.
A. For non-solenoid operated valves: Submerge the valve in clean mineral
spirits to flush out contamination. If the valve design allows, use a
non–metallic probe to push the internal spool in and out 20 to 30 times
to flush out contamination. Clean and dry the cartridge valve with
compressed air.
B. For solenoid operated valves: Temporarily install the solenoid on the
cartridge valve and connect a 12 volt power source to the solenoid.
While energized, flush out any contamination with a nonflammable
aerosol brake cleaner. De-energize the solenoid. Repeat the flush
while energized procedure 5 or 6 times. Remove the solenoid from the
cartridge.
5–27).
IMPORTANT
CAUTION
Page 4–102
Testing a
General Precautions for
4–71).
Greensmaster 3120
17230SL Rev C