jcb JS300 Service Manual page 793

Motor Brake Working Poorly
Symptom
Low brake torque.
Motor is Driven by Exterior Torque
Symptom
Slip volume is high.
Oil Leakage
Symptom
Oil leaking from around the drive
shaft oil seal.
Oil leaking from mating surfaces of
main housing and valve housing.
E-132
Cause
The friction plate is worn out.
The brake piston is sticking.
The brake releasing pressure is low.
The spline of the friction plate is broken.
Cause
The relief valve is not set correctly.
Relief valve plunger not seating cleanly.
The reversal protecting valve does not
work properly.
Drain volume exceeds 500 cc/mm.
Cause
Oil seal lip damaged.
The shaft is damaged or worn.
High pressure in casing, causing the lip of
the oil seal to become rolled.
The drive shaft is corroded.
O-ring not fitted or damaged.
The seal surface is damaged.
The securing bolts are damaged or loose. Renew and/or tighten to the required
9813/5100-1
Section E - Hydraulics
Swing Motor
Remedy
Dismantle and renew worn parts.
Dismantle and clean.
Check and repair the supply circuit.
Dismantle and renew the broken parts.
Remedy
Set to correct value or renew.
Renew.
Renew.
Dismantle and check for signs of wear.
Renew suspect parts.
Remedy
Renew the oil seal.
Repair or renew the shaft.
Clear the drain pipes.
Dismantle and repair.
Fit or renew the O-ring.
Dismantle and repair.
torque.
Fault Finding
E-132