Sakai SV410-2, Shop Manual

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9-063
TROUBLESHOOTING
3-5. Blade (SV410TB
-2
, FB
-2
)
If a problem occurs in the blade control system, determine the cause and carry out action as required, according to
the following general troubleshooting items.
(NOTICE)
When checking whether or not the pressure is correct, refer to the pressure standard value for each
hydraulic circuit.
3-5-1. Blade up/down operation not possible
Check point Cause Check/Action
1. Oil Level of
Hydraulic Oil Tank
Oil level in hydraulic oil tank is low. Fill tank until correct oil level is obtained.
2. Flow Dividing Valve
(Steering Blade) for
Separation
Oil flow is not divided because spool is stuck
on one side, interrupting hydraulic circuit.
Clean spool or replace it if necessary.
3. Blade Circuit
Pressure
Circuit does not obtain required pressure
because setting pressure of stack valve
relief valve is low.
Measure blade circuit pressure.
If low, inspect stack valve relief valve or
replace it if necessary.
•
•
4. Stack Valve Blade cylinder does not operate because
stack valve spool does not change.
If stack valve lever does not move, check
and clean spool, or replace stack valve.
5. Blade Cylinder Cylinder thrust decreases due to internal
leakage of blade cylinder.
Repair blade cylinder or replace it if
necessary.
6. Suction Filter for
Steering • Charge
Pump
Steering • charge pump discharge rate
decreases due to clogged filter.
Clean suction filter or replace it if necessary.
7. Steering • Charge
Pump
Discharging pressure is insufficient due to
efficiency degradation of steering • charge
pump.
Measure the steering circuit pressure.
If low, replace steering • charge pump.
•
•
3-5-2. Blade movement is slow or force is small
Check point Cause Check/Action
1. Oil Level of
Hydraulic Oil Tank
Oil level in hydraulic oil tank is low. Fill tank until correct oil level is obtained.
2. Stack Valve Oil bypassing because relief valve is open. Measure blade circuit pressure.
If low, inspect relief valve or replace it if
necessary.
•
•
3. Blade Cylinder Internal leakage of blade cylinder Repair blade cylinder or replace it if
necessary.
4. Suction Filter for
Steering • Charge
Pump
Steering • charge pump discharge rate
decreases due to clogged filter.
Clean suction filter or replace it if necessary.
5. Steering • Charge
Pump
Discharge rate is insufficient due to
efficiency degradation of steering • charge
pump.
Measure the steering circuit pressure.
If low, replace steering • charge pump.
•
•
•