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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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