Groundsmaster 4300--D Hydraulic SystemPage 4 -- 93
NOTE: The deck control manifold uses several z ero
leak plugs. These plugs have a tapered sealing surface
on the plug head that is designed to resist vibration in-
duced plug loosening. The zero leak plugs also have an
O--ring to provide a secondary seal. If z ero leak plug re-
moval is necessary, lightly rap the plug head using a
punch and hammer before using an allen w rench to re-
move the plug: the impact w ill allow plug removal with
less chance of damage to the socket head of the plug.
When installing plugs into the control manifold, torque
plugs to the values identified in Figures 81.
Deck Control Manifold Service
1. Make sure themanifold is thoroughly cleaned before
removing any cartridge valve.
2. If solenoid cartridge valve is being serviced, remove
nutsecuring solenoid coil to the cartridge valve. Careful-
ly slide solenoid coil off the valve.
CAUTION
Before opening hydraulic system, operateall hy-
draulic controls to relieve system pressure and
avoid injury from pressurized hydraulic oil. See
Relieving Hydraulic System Pressure in the Gen-
eral Information section of this chapter.
IMPORTANT: Use care when removing cartridge
valves. Slight bending or distortion of the stem tube
can cause binding and malfunction. Make sure that
deep well socket fully engages the valve base.
3. Using a deep well socket, remove cartridge valve
from manifold. Note correct location of O--rings, sealing
rings and backup rings. Remove and discard seal kit
from valve.
4. Visually inspect the manifold port for damage to the
sealing surfaces, damaged threads and contamination.
5. Visually inspect cartridge valve for damaged sealing
surfaces and contamination.
A. Contamination may cause valves to stick or hang
up.Contaminationc an become lodged in small valve
orifices or seal areas causing valve malfunction.
B. If valve sealing surfaces appear pitted or dam-
aged, the hydraulic system may be overheating or
there may be water in the system.
CAUTION
Use eye protection such as goggles when using
compressed air for cartridge valve cleaning.
CAUTION
Abrupt movement of internal spools can cause
stored fluid to be released suddenly.
6. Clean cartridge valve by submerging valve in clean
mineral spirits to flush out contamination. Particles as
fine as talcum powder can affect the operation of high
pressure hydraulic valves. If cartridge design allows,
use a wood or plastic probe to push the internal spool in
and out20 to 30 times to flush out contamination. Be ex-
tremely careful not to damage cartridge. Use com-
pressed air for cleaning.
7. Reinstall cartridge valve into manifold:
A. Lubricate new seal kit components with clean hy-
draulic oil and install on valve. The O--rings, sealing
rings and backup rings must be arranged properly on
the cartridge valve for proper operation and sealing.
IMPORTANT: Use care when installing cartridge
valves. Slight bending or distortion of the stem
tube can cause binding and malfunction. Make
sure that deep well socket fully engages the
valve base.
B. Threadcartridge valve carefully intocorrect man-
ifold port. The valve should go in easily without bind-
ing.
C. Torque cartridge valve using a deep well socket
to values identified in Figure 81.
8. If solenoid coil was removed from cartridge valve:
A. Carefully install coil onto the valve.
B. Install nut and torque nut to 60 in--lb (6.7 N--m).
Hydraulic
System
