jcb JS300 Service Manual page 792

Motor Does Not Rotate
Symptom
The pressure is low.
The pressure is correct but no
rotation.
Motor Rotates in the Reverse Direction
Symptom
Reverse rotation.
Motor Speed is Low
Symptom
Slow rotation.
E-131
Fault Finding
Cause
The relief valve is not set correctly.
The relief valve does not work properly.
Plunger sticking.
Plunger orifice contaminated.
Plunger not seating correctly.
Overload protection operating.
The moving part is burnt.
No release pressure acting on the rake.
The brake piston is sticking.
The brake friction plate is burnt and
sticking to counter plate.
Cause
The motor has been incorrectly
assembled.
Inlet/outlet hoses reversed.
Cause
The oil flow volume is low.
The temperature is high and leakage is
serious.
The sliding parts are worn out or broken. Renew suspect parts.
9813/5100-1
Section E - Hydraulics
Swing Motor
Remedy
Set to the correct value.
Repair or renew the plunger.
Dismantle and clean.
Renew the plunger seat.
Remove the cause of overload.
Check and repair the piston/shoe,
cylinder/valve plate, etc.
Check and repair the circuit.
Dismantle and clean/repair.
Dismantle and renew the damaged parts.
Remedy
Check step 16 of the Assembly procedure
to verify that the valve housing 303 and
main housing 301 are in their correct
relative positions. Rectify if necessary.
Re-locate hoses.
Remedy
Check the pump output and the circuit to
the motor.
Check the oil cooling circuit.
Fault Finding
E-131