Service Manual

Groundsmaster 3500Hydraulic System Page 5 − 108
Cartridge Valve Service (Fig. 67 and 68)
NOTE: The ports on the manifold are marked for easy
identification of components. Example: port LV con-
nects the the lift valve circuit and port P1 connects the
gear pump (P1). See Hydraulic Schematics in this
chapter to identify the function of the hydraulic lines and
cartridge valves at each port location.
NOTE: The Groundsmaster 3500 hydraulic manifold
uses several zero leak plugs. These plugs have a ta-
pered 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 re-
moval with less chance of damage to the socket head of
the plug.
1. Make sure the manifold is clean before removing the
valve.
2. If cartridge is solenoid operated, remove nut secur-
ing solenoid to the cartridge valve. Carefully slide sole-
noid coil off the valve.
IMPORTANT: Use care when handling the cartridge
valve. Slight bending or distortion of the stem tube
can cause binding and malfunction.
3. Remove cartridge valve with a deep socket wrench.
Note correct location for O–rings, sealing rings and
backup rings. Remove and discard seal kit.
4. Visually inspect the port in the manifold for damage
to the sealing surfaces, damaged threads or contamina-
tion.
5. Visually inspect cartridge valve for damaged sealing
surfaces and contamination.
A. Contamination may cause valves to stick or hang
up. Contamination can become lodged in small valve
orifices or seal areas causing 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.
6. Clean cartridge valve using clean mineral spirits.
Submerge valve in clean mineral spirits to flush out con-
tamination. Particles as fine as talcum powder can affect
the operation of high pressure hydraulic valves. Be ex-
tremely careful not to damage cartridge. Use com-
pressed air for cleaning.
7. Reinstall the cartridge valve into the manifold block:
A. Lubricate new seal kit components with clean hy-
draulic fluid and install on valve. The O–rings, seal-
ing rings and backup rings must be arranged
properly on the cartridge valve for proper operation
and sealing.
IMPORTANT: Use care when handling the valve
cartridge. Slight bending or distortion of the
stem tube can cause binding and malfunction.
B. Thread cartridge valve carefully into manifold
port. The valve should go in easily without binding.
C. Torque cartridge valve using a deep socket to val-
ue identified in manifold illustrations (Fig. 67 and 68).
D. If cartridge is solenoid operated, carefully install
solenoid coil to the cartridge valve. Torque solenoid
nut to 60 in−lbs (6.8 N−m).
8. If problems still exist, remove valve and clean again
or replace valve.