Sakai SW300-1, Shop Manual

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10-055
TROUBLESHOOTING
3-2-1. Machine moves neither forward nor backward 2/2
Check point Cause Check/Action
8. Propulsion Pump Discharge fl ow rate is insuf fi cient due to
ef fi ciency degradation of propulsion pump.
• Measure discharge fl ow rate of propulsion
pump with fl ow meter.
• If discharge fl ow rate is not within speci fi ed
range, repair propulsion pump or replace it
if necessary.
Discharge fl ow rate is insuf fi cient due to
wear of propulsion pump drive shaft splines.
Replace propulsion pump.
Propulsion circuit pressure is not held in
propulsion pump case. If pressure in propulsion pump case is not
within allowable range, repair propulsion
pump or replace it if necessary.
9. Parking Brake
Solenoid Valve
Brake remains applied because spool of
parking brake solenoid valve does not shift. Repair parking brake solenoid valve or
replace it if necessary.
10. Brake Inlet
Pressure
Brake cannot be released because brake
inlet pressure is low. • Measure brake release pressure.
• If low, repair or replace propulsion motor.
11. Coupling Drive torque is not transmitted to pump due
to faulty coupling. Replace coupling.
3-2-2. Machine moves in one direction only (forward or backward)
Check point Cause Check/Action
1. F-R Lever Linkage F-R lever linkage is faulty. Check and adjust F-R lever linkage or
replace it if necessary.
2. High Pressure
Relief Valve
Low circuit pressure due to incorrect high
pressure relief setting or internal leakage of
high pressure relief valve. • Interchange two high pressure relief
valves.
• If faulty condition is accordingly reversed,
inspect high pressure relief valve or
replace it if necessary.
3-2-3. Slow machine speed or small drive force 1/2
Check point Cause Check/Action
1. F-R Lever Linkage F-R lever linkage is faulty. Check and adjust F-R lever linkage or
replace it if necessary.
2. Bypass Valve Bypass valve is slightly open. Inspect high pressure relief and bypass
valves or replace them if necessary.
3. Charge Circuit
Pressure
Stroke of propulsion pump swash plate
is small because charge pressure is low,
decreasing discharge rate of propulsion
pump. • Measure charge pressure.
• If low, check and adjust charge relief valve
or replace it if necessary.
Insuf fi cient charge pump discharge. Repair charge pump or replace it if
necessary.
Charge pressure decreases due to internal
leakage of solenoid valve connecting oil
supply circuit with charge circuit.
• Parking brake solenoid valve
• When solenoid is energized, check if oil
fl ows in return circuit to tank.
• If oil is fl owing, repair solenoid valve or
replace it if necessary.
4. Suction Filter for
Charge Pump
Flow rate of charge pump decreases as
well as charge pressure decreases due to
clogged
fi lter.
Clean suction fi lter or replace it if necessary.
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