Sakai SV510-III, Shop Manual

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9-068
TROUBLESHOOTING
3-2-1. Machine moves neither forward nor backward 2/2
Check point Cause Check/Action
9. Brake Solenoid
Valve
Brake remains applied because spool of
brake solenoid valve does not shift.
Repair 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, replace rear axle.
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11. Rear Axle Sticking of disc brakes causes brakes to
remain applied.
Replace disc brakes.
12. Flange Drive torque is not transmitted to pump due
to faulty flange.
Replace flange.
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. Multifunction Valve Low circuit pressure due to incorrect high
pressure relief setting or internal leakage of
multifunction valve.
Interchange two multifunction valves.
If faulty condition is accordingly reversed,
check and adjust multifunction valve or
replace it if necessary.
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3-2-3. Slow machine speed or small drive force 1/2
Check point Cause Check/Action
1. Bypass Valve Bypass valve is slightly open. Close bypass valve completely.
2. F-R Lever Linkage F-R lever linkage is faulty. Check and adjust F-R lever linkage or
replace it 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.
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Insufficient 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
flows in return circuit to tank.
If oil is flowing, repair solenoid valve or
replace it if necessary.
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4. Suction Filter for
Charge Pump
Flow rate of charge pump decreases as
well as charge pressure decreases due to
clogged filter.
Clean suction filter or replace it if necessary.
5. Propulsion Motor Propulsion motor inlet pressure is low. Measure propulsion motor inlet pressure.
If low, check and adjust multifunction valve
or replace it if necessary.
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Propulsion circuit pressure is not held in
propulsion motor case.
If pressure in propulsion motor case is not
within allowable range, repair propulsion
motor or replace it if necessary.
Output of propulsion motor decreases and
number of revolutions decreases due to
internal leakage of propulsion motor.
Measure drain quantity from propulsion
motor.
If drain quantity is larger than standard
value, repair propulsion motor or replace it
if necessary.
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