Toro Groundsmaster 4300-D Service Manual page 190

Servicing the Deck Control Manifold Assembly
Hydraulic System: Service and Repairs
Note: The ports on the deck control manifold are marked for easy identification
of the components. Example: P1 is the pump P1 connection port and PRV2
is the location for the proportional relief valve PRV2; refer to the Hydraulic
Schematic in Appendix A—Foldout Drawings to identify the function of the
hydraulic lines and cartridge valves at each manifold port.
Note: The deck control manifold uses several zero-leak plugs. These plugs have
a tapered sealing surface on the plug head that is designed to resist vibration
induced plug loosening. The zero-leak plugs also have an O-ring as a secondary
seal. If zero-leak plug removal is necessary, lightly rap the plug head using a
punch and hammer before using an allen wrench to remove the plug: the impact
will allow plug removal with less chance of damage to the socket head of the plug.
When installing the plugs; torque the plugs to the values identified in
Before opening the hydraulic system, operate all the hydraulic
controls to release all the pressure in the system and avoid injury
from pressurized hydraulic fluid; refer to
the Hydraulic System (page
1. Ensure that the entire outer surface of the manifold is clean before you
remove the cartridge valve.
2. If the solenoid cartridge valve is being serviced, remove the nut that secures
the solenoid coil to the cartridge valve. Carefully slide the solenoid coil off
the valve.
Carefully handle the valve cartridge. Slight bending or distortion of
the stem tube can cause binding and malfunction. When removing
the cartridge valve from the control manifold, ensure that the deep
well socket fully engages the valve base.
3. Remove the cartridge valve with a deep well socket wrench. Note the correct
location of the O-rings, sealing rings, and back-up rings.
4. Remove and discard the seal kit.
5. Visually examine the port in the manifold for damaged sealing surfaces,
damaged threads, and contamination. Also, inspect the cartridge valve for
damaged sealing surfaces and contamination.
A. Contamination can cause the valves to stick or hang up. Contamination
can accumulate in small valve orifices or seal areas and cause
malfunction.
B. If the sealing surfaces of the valve are pitted or damaged, the hydraulic
system can be too hot or there can be water in the system.
Use the eye protection such as goggles when using the
compressed air.
WARNING
4–6).
IMPORTANT
CAUTION
Page 4–128
Figure
Releasing Pressure from
Groundsmaster
16226SL Rev C
99.
® 4300-D