Hitachi ZAXIS 17U-5N Owner's Manual page 239

Swing Function
Problem
Upperstructure does not swing.
Swing is not smooth.
Immediately after the control valve, swing motor relief valve and/or the swing motor is replaced, a noise may be
emitted and/or operation may not be performed smoothly due to air trapped in the hydraulic line.
Slowly continue to operate the machine for approx. 10 minutes to bleed air.
After repair work is complete, be sure to check the oil level in the hydraulic oil tank. Refill hydraulic oil as needed.
Others
The machine may have a noise, excessive vibration, and abnormal smell when any trouble occurs.
Always beware of the machine conditions during operation.
TROUBLESHOOTING
Cause
Faulty swing parking brake
Broken swing motor
Faulty pilot valve
Faulty pilot circuit line
Low set pressure of swing relief valve
Worn swing gear
Damaged swing bearing and bearing balls
Lack of grease
Low set pressure of swing relief valve
11-7
* Repair or replace
* Repair or replace
* Replace
* Repair or replace
* Adjust and replace
* Repair or replace
* Repair or replace
Refill
* Adjust and replace
* Mark: Consult your authorized Hitachi dealer.
Solution