Kubota U25-3 Repair Manual

U20-3, U25-3 WSM Hydraulic system (Service section)
IV-S-8
e. Swivel performance
First make sure the swivel mechanism alone is in trouble.
Problem Cause Correction
1
No swiveling in both
directions
(2) Pilot valve spool malfunctioning
Check the performance. Overhaul
and clean.
(3) Control valve spool stick malfunctioning
Check the performance. Overhaul
and clean.
(4) Pilot secondary pressure unspecified Measure the pressure.
(5) Brake poorly unlocked Measure the pressure.
(6) Brake valve pressure unspecified
Measure the pressure. Overhaul,
clean and readjust.
(7) Anti-void valve malfunctioning, valve seat defective Overhaul and clean.
(8) Motor drain too much Measure the drain amount.
(9) Motor internal parts damaged Overhaul, clean and replace.
(10) Control valve internal parts damaged Overhaul, clean and replace.
2
No swiveling in one
direction
(2) Pilot valve spool malfunctioning
Check the performance. Overhaul
and clean.
(3) Control valve spool stick malfunctioning
Check the performance. Overhaul
and clean.
(4) Pilot secondary pressure unspecified Measure the pressure.
(6) Brake valve pressure unspecified
Measure the pressure. Overhaul,
clean and readjust.
(7) Anti-void valve malfunctioning, valve seat defective Overhaul and clean.
(8) Motor drain too much Measure the drain amount.
(9) Motor internal parts damaged Overhaul, clean and replace.
(10) Control valve internal parts damaged Overhaul, clean and replace.
3
No enough power.
Too slow motion
(2) Pilot valve spool malfunctioning
Check the performance. Overhaul
and clean.
(3) Control valve spool stick malfunctioning
Check the performance. Overhaul
and clean.
(4) Pilot secondary pressure unspecified Measure the pressure.
(6) Brake valve pressure unspecified
Measure the pressure. Overhaul,
clean and readjust.
(7) Anti-void valve malfunctioning, valve seat defective Overhaul and clean.
(8) Motor drain too much Measure the drain amount.
(9) Motor internal parts damaged Overhaul, clean and replace.
(10) Control valve internal parts damaged Overhaul, clean and replace.
4
No stop even at neutral
position.
Overrunning
(2) Pilot valve spool malfunctioning
Check the performance. Overhaul
and clean.
(3) Control valve spool stick malfunctioning
Check the performance. Overhaul
and clean.
(6) Brake valve pressure unspecified
Measure the pressure. Overhaul,
clean and readjust.
(7) Anti-void valve malfunctioning, valve seat defective Overhaul and clean.
(8) Motor drain too much Measure the drain amount.
5
Too high shock at start
and stop.
No inching operation
(2) Pilot valve spool malfunctioning
Check the performance. Overhaul
and clean.
(3) Control valve spool stick malfunctioning
Check the performance. Overhaul
and clean.
(7) Anti-void valve malfunctioning, valve seat defective Overhaul and clean.
(6) Brake valve pressure unspecified
Measure the pressure. Overhaul,
clean and readjust.
(8) Motor drain too much Measure the drain amount.

Kubota U25-3 Specifications

General

Brand	Kubota
Model	U25-3
Category	Excavators
Language	English