Sakai SW800-II, Shop Manual

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10-076
TROUBLESHOOTING
3-2-1. Vehicle 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 or replace brake solenoid valve.
10. Brake Brake cannot be disengaged because brake
discs in propulsion motor are stuck.
Measure brake release pressure. If high,
repair brake discs in propulsion motor or
replace it if necessary.
11. Coupling Drive torque is not transmitted to pump due
to faulty coupling.
Replace coupling.
3-2-2. Vehicle 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.
Interchange two high-pressure relief valves.
If faulty condition is accordingly reversed,
check and adjust high-pressure relief valve
or replace it if necessary.
3-2-3. Slow vehicle speed or small drive force
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.
Insufficient charge pump discharge. Repair or replace charge pump.
Charge pressure decreases due to internal
leakage of solenoid valve connecting oil
supply circuit with charge circuit.
Brake solenoid valve •
When solenoid is energized, check if oil
flows in return circuit to tank. If so, carry out
following action.
Repair or replace brake solenoid valve. •
4. Suction Filter for
Charge Pump
Flow rate of charge pump decreases as
well as charge pressure decreases due to
clogged filter.
Clean or replace suction filter.
5. Propulsion Motor
Inlet Pressure
Propulsion motor inlet pressure is low. Measure propulsion motor inlet pressure. If
low, check and adjust high-pressure relief
valve or replace it if necessary.
6. Internal Leakage of
Propulsion Motor
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.
7. Propulsion Pump Discharge flow rate is insufficient due to
efficiency degradation of propulsion pump.
Measure discharge flow rate of propulsion
pump with flow meter. If discharge flow
rate is not within specified range, repair
propulsion pump or replace it if necessary.