Kubota KX080-4 Workshop Manual page 325

KX080-4, WSM
Boom operation slow or jerky
No. Cause
Anti-drop check valve sticking or
1 damaged
Shockless valve faulty
2
P3 bypass spool sticking
3
Arm operation slow or jerky
No. Cause
Arm regenerative valve faulty
1
Swing slow or fails to move
No. Cause
Swing external orifice faulty
1
Swing extends or contracts
No. Cause
Anti-void faulty
1 1. Seat NG: extends
2. Suction NG: makes it sway
When lever operated, it goes down and then back up
No. Cause
Load check valve inside the control valve
1
faulty
A great deal of hydraulic drift.
No. Cause
1. Leak inside a cylinder
2. Leak inside a control valve
1
Overload relief valve faulty
2
Remedy
• Inspect the anti-drop check valve
1. Remove the anti-drop check valve from the control valve.
2. Check the inside and inspect for abnormalities.
• Clean or replace the shockless valve
1. Clean the spool
2. Replace the valve
Remedy
• Inspect the arm regenerative valve
1. Take the spool out of the control valve and clean it.
2. Check the inside and inspect for abnormalities.
Remedy
• Clean swing external orifice
If same thing happens: problem with anti-void and/or shut-off valves
Remedy
• Disassemble and clean or replace the anti-void valve
Remedy
• Inspect the load check valve.
Remove and clean the load check valve.
Remedy
• Measure the hydraulic drift
If hydraulic drift is outside of factory specs, take the following steps.
1. Exchange hoses with a normally operating section (on control
valve side).
2. Test the hydraulic drift again.
[Assessment]
Within factory specs: control valve and/or overload relief valve faulty
Outside specs: cylinder seals faulty
• Diagnose the overload relief valve
Temporarily replace with a known good overload relief valve and
determine whether faulty or not.
3-S166
HYDRAULIC SYSTEM
Notes
RY9212158HYS0109US0
Notes
RY9212148HYS0357US0
Notes
RY9212148HYS0358US0
Notes
RY9212148HYS0359US0
Notes
RY9212148HYS0360US0
Notes
RY9212148HYS0361US0
KiSC issued 08, 2015 A