Hyster W20-30ZR, Manual

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2000 SRM 1025 Relief Valve Adjustment
12. 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.
13. Check hydraulic oil level in reservoir and fill to
proper level. See Table 1.
14. Test lift truck by lifting and lowering a load sev-
eral times. Check for leaks.
15. Install the drive unit compartment cover. If nec-
essary, install the hydraulic unit compartment
cover.
Relief Valve Adjustment
WARNING
Do not make repairs or adjustments unless you
have both authorization and training. Incor-
rect repairs and adjustments can create dan-
gerous operating conditions. Do not operate a
lift truck that needs repairs. Report the need
for repairs to your supervisor immediately. If
repair is necessary, put a DO NOT OPERATE
tag on the control handle. Remove the key from
the key switch and disconnect the battery.
1. Check hydraulic oil level in reservoir when oil
is at room temperature, forks fully lowered, and
mast vertical. See Table 1 for the proper level.
2. Operate lift truck until hydraulic oil reaches op-
erating temperature.
3. Lower forks completely to relieve pressure from
hydraulic system. Remove key from switch and
disconnect battery.
4. Remove the drive unit compartment cover. On
W25/30/40ZC trucks, also remove the hydraulic
compartment cover.
5. Turn key switch to OFF position and disconnect
battery.
6. Block load wheels to prevent lift truck from mov-
ing. Refer to Periodic Maintenance 8000 SRM
1027.
7. Discharge the capacitor. See Special Precau-
tions.
WARNING
Hydraulic oil hoses and lines may be under
high pressure. Hydraulic oil can be injected
into the body by pressure. To prevent possible
injury, shield yourself from any escaping oil.
Wrap a rag around the fitting and loosen the
fitting and loosen the connection slowly.
8. Disconnect the lift circuit pressure line at the
pump.
9. Install a tee fitting and a pressure gauge of at
least 21 MPa (3000 psi) capacity.
10. Connect the battery.
11. Verify the oil is at operating temperature.
12. Raise the forks completely and read the pressure
gauge.
NOTE: The pump may stop after a short period of
time.
Press the lower button briefly to reset the
pump time-out circuit.
13. Correct relief pressure is 20 MPa (2900 psi).
CAUTION
To prevent damage to the relief valve adjust-
ment screw, always loosen the locking nut
prior to turning relief valve adjustment screw.
14. If the relief pressure is incorrect:
a. Loosen the lock nut.
b. Adjust the relief valve adjustment screw
in small increments. Turn the adjustment
screw clockwise to increase pressure. Turn
the adjustment screw counterclockwise to
decrease pressure.
c. Tighten the lock nut and torque to 19 N•m
(14 lbf ft).
d. Recheck the relief pressure.
e. Repeat as necessary, until the correct relief
pressure is measured.
15. Lower forks completely to relieve pressure from
hydraulic circuit. Turn key switch to OFF posi-
tion.
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