Sakai R2H-2, Shop Manual

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10-066
TROUBLESHOOTING
3-2. Propulsion System
If a problem occurs in propulsion systems such as propulsion pump, propulsion motor and brakes, determine the
cause and carry out action as required, according to following general troubleshooting items.
(NOTICE)
• When checking whether or not the pressure is correct, refer to the pressure standard value for each
hydraulic circuit.
3-2-1. Machine moves neither forward nor backward 1/2
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. Bypass Valve Bypass valve is open. Close bypass valve.
3. F-R Lever Linkage F-R lever linkage is faulty. Check and adjust F-R lever linkage or
replace it if necessary.
4. Charge Circuit
Pressure
Propulsion pump does not discharge oil
because charge pressure is low.
• Measure charge pressure.
• If low, check and adjust charge relief valve
or replace it if necessary.
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
• Speed change 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.
5. Servo Bypass
Solenoid Valve
If spool of servo bypass solenoid valve is
stuck, pressure in both sides of servo
cylinder chamber is equalized. This causes
propulsion pump unable to discharge oil.
• Measure pressure in servo cylinder
chambers.
• If pressure is equal in both chambers,
repair servo bypass solenoid valve or
replace it if necessary.
6. Suction Filter for
Charge Pump
Charge pump flow is reduced due to
clogged filter.
Clean suction filter or replace it if necessary.
7. Propulsion Circuit
Pressure
Circuit does not obtain required pressure
because setting pressure of high pressure
relief is low.
• Measure propulsion circuit pressure.
• If low, check and adjust multifunction valve
or replace it if necessary.
8. Propulsion Motor 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.
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.
Sticking of disc brakes causes brakes to
remain applied.
Replace disc brakes.