Hyster W20-30ZR, Manual

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Valve Repair 2000 SRM 1025
5. Disconnect the overhead lifting device from the
mast.
6. Connect battery and turn key switch to ON posi-
tion.
7. Operate each hydraulic function several times to
purge the air from the hydraulic circuit.
8. Check the top of the lift cylinder to determine if
a buttonhead bleed screw is present. If a bleed
screw is present, bleed the air from the hydraulic
system. See Bleed Hydraulic System.
9. Check hydraulic oil level in reservoir and fill to
proper level. See Table 1.
10. Test lift truck by lifting and lowering a load sev-
eral times. Check for leaks.
11. Install the drive unit compartment and the hy-
draulic unit compartment cover.
RELIEF VALVE AND CHECK VALVE
NOTE: The relief valve and check valve are located
on the lift pump assembly.
Remove
1. Move lift truck to a safe and level area.
2. Lower the forks completely to relieve pressure
from the hydraulic system.
3. Turn key switch to OFF position and disconnect
battery.
4. Block load wheels to prevent lift truck from mov-
ing. Refer to Periodic Maintenance 8000 SRM
1027.
5. Remove the drive unit compartment cover. On
W25/30/40ZC lift trucks, also remove the hy-
draulic compartment cover.
6. Discharge the capacitor. See Special Precau-
tions.
7. If necessary, tag and disconnect the power wires
to obtain adequate clearance to tilt the lift pump
and motor assembly away from the frame.
8. If necessary, remove the two nuts and washers
attaching the mounting bracket to the isolators
and tilt the lift pump and motor assembly away
from the frame.
9. Slowly loosen the relief valve cartridge to relieve
pressure.
10. Remove the relief valve cartridge.
11. If necessary, remove the check valve cartridge us-
ing a 90 mm (3.5 in.) long M8 bolt. Thread the
bolt into the cartridge to pull it from the housing.
Install
1. Verify that the O-rings on the valve cartridges
are not damaged. Replace as needed.
2. Verify that the valve cartridges and pump hous-
ing are clean and not damaged.
3. Lubricate the relief valve cartridge threads and
the O-rings on both valve cartridges with clean
hydraulic oil.
4. If removed, install the check valve cartridge.
5. Install the relief valve cartridge and torque to
32 N•m (23.5 lbf ft).
6. If removed, install the two nuts and washers
connecting the mounting bracket and isolators.
Torque the nuts to 15 N•m (11 lbf ft).
7. If removed, connect the power wires to the lift
pump motor with the two nuts and washers.
Torque the nuts to 4.0 N•m (35 lbf in).
8. Connect battery and turn key switch to ON posi-
tion.
9. Operate each hydraulic function several times to
purge the air from the hydraulic circuit.
10. Check the top of the lift cylinder to determine if
a buttonhead bleed screw is present. If a bleed
screw is present, bleed the air from the hydraulic
system. See Bleed Hydraulic System.
11. Check hydraulic oil level in reservoir and fill to
proper level. See Table 1.
12. Verify that the relief valve settings are correct.
See Relief Valve Adjustment.
PILOT OPERATED CHECK VALVE
W20/30ZR
NOTE: The pilot operated check valve is located on
the mast.
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