Troubleshooting (Continued)
Problem
Cause
Correction
Maximum swing action
Bent piston rod in cylinder
Replace or rebuild the cylinder; replace
cannot be obtained
damaged parts.
Something jamming the swing
Remove interference.
linkage
Slow operation of machine
Low oil supply in reservoir
Fill to proper level.
(lack of power) all cylinders
Oil viscosity too heavy, or oil
Use recommended hydraulic fluid. Run
is not at operating temperature
machine until oil reaches operating
temperature.
Insufficient pumping
Advance engine throttle.
Divertor valve on prime mover
Divertor valve may need rebuilding or
leaking externally or bypassing
replacing.
oil internally through valve to
reservoir.
Excessive back pressure
Relieve condition. Restriction may be
from outlet to reservoir.
Relief valve setting in backhoe
Relief pressure will have to be checked
control valve too low or defective
and corrections made. Backhoe
system pressure is 2000 PSI (CBH60),
2250 PSI (CBH70), 2550 PSI (CBH80),
Relief valve may need cleaning and
overhauling, or entire cartridge must be
replaced.
Spongy or jerking action
Low oil supply in reservoir
Fill to proper level.
of cylinders and/or noisy
operation
Air in system
Bleed all circuits of air by operating
machine at maximum oil flow and
through full movements.
Oil viscosity too heavy, or
Use recommended hydralic fluid. Run
oil is not at operating
machine until oil reaches operating
temperature
temperature.
Pump not running
Check pump drive to be sure it is
engaged.
Lift, crowd or bucket
Damaged or worn spool
Replace spool end seals.
cylinders drop under load
seals
when control spools
shifted from neutral
Problems involving the control
This valve is a precision device and is
valve
not intended for any extensive field
adjustment or repair. Field replace-
ment parts are limited to seal kits,
cartridges, valve sections and tie rods.
Replacement of these parts, the
opening of check cavities and certain
relief cavities to examine for trapped
dirt, or resetting of the main relief valve
with the use of good pressure gauge,
should be referred to qualified service
personnel.
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