Kubota U20-3 Workshop Manual page 320

U20-3, U25-3 WSM
Problem
The swing mechanism alone
fails or responds too slow or too
weak.
The dozer alone fails or
responds too slow or too weak.
The boom cylinder allows too
much gravity fall.
The bucket cylinder and arm
cylinder allow too much gravity
fall.
The swing cylinder still works at
neutral position.
The dozer cylinder allows too
much gravity fall.
The hydraulic oil tank
temperature is too high.
Cause
(1) Swing pedal and link maladjusted.
(2) Control valve swing section spool
malfunctioning.
(3) Anti-void valve defective.
(4) Swing cylinder rod packing broken.
(1) Dozer overload relief valve not at specified
pressure.
(2) Dozer lever and cable maladjusted.
(3) Control valve dozer section spool
malfunctioning.
(4) Dozer cylinder rod packing broken.
(1) Overload relief valve not at specified pressure.
(2) Control valve's anti-drift valve malfunctioning.
(3) Control valve spool scratched or spring
broken.
(4) Boom cylinder rod packing broken.
(1) Overload relief valve not at specified pressure.
(2) Control valve spool scratched or spring
broken.
(3) Bucket cylinder or arm cylinder rod packing
broken.
(1) Swing pedal linkage maladjusted.
(2) Anti-void valve defective.
(3) Control valve spool stick or spring broken.
(4) Swing cylinder rod packing broken.
(1) Overload relief valve not at specified pressure.
(2) Control valve spool scratched or spring
broken.
(3) Dozer cylinder rod packing broken.
(1) Hot air backflow due to damaged partition
around oil cooler.
(2) Oil cooler clogged.
(3) Return filter clogged.
(4) Low-pressure line clogged with foreign
matters.
IV-S-5
Hydraulic system (Service section)
Correction
Check the pedal and link and readjust as
required.
Check the spool and repair as required.
Check the anti-void valve and replace as
required.
Overhaul the cylinder and replace the
sealing.
Check the overload relief valve and repair
as required.
Check the lever and cable and readjust as
required.
Check the spool and repair as required.
Overhaul the cylinder and replace the
sealing.
Check the overload relief valve and repair
as required.
Check the anti-drift valve and repair as
required.
Check the spool and repair as required.
Overhaul the cylinder and replace the
sealing.
Check the overload relief valve and repair
as required.
Check the spool and repair as required.
Overhaul the cylinder and replace the
sealing.
Check the linkage and readjust as
required.
Check the anti-void valve and repair as
required.
Check the spool and repair as required.
Overhaul the cylinder and replace the
sealing.
Check the overload relief valve and repair
as required.
Check the spool and repair as required.
Overhaul the cylinder and replace the
sealing.
Check the oil cooler and its surrounding.
Clean the oil cooler.
Check the return filter and replace as
required.
Check the low-pressure line.