IV-54
HYDRAULIC UNITS
CONTROL VALVE
TROUBLESHOOTING
The following items are a list of all the problems
that might occur individually, but in actual practice,
2 or 3 of these problems might occur simultaneously
Symptom
Probable Causes
Remedy
Oil leaks from spool
seal.
• Seal is scratched or the seal lip is worn
due to long use.
• Spool
·
s seal sliding portion was dam-
aged by some external cause (bruise,
scratch, etc.).
• Seal bulged out and the cover was in-
stalled in a warped state.
• Paint adhered to the sliding portion of
the spool
·
s seal portion during painting.
• Tank circuit
·
s pressure became high and
exceeded the pressure level that the seal
was capable of withstanding.
• Replace with a new part.
• Repair or replace the spool.
• Return to the correct shape and check
for eccentric wear of the seal lip.
• Remove paint with paint thinner or re-
move it mechanically. However, at this
time, be careful not to damage the spool
surface or the seal lip.
• Eliminate the factors causing excessive
flow resistance.
Spool
·
s sliding is not
smooth.
• Foreign matter is biting into the spool
·
s
sliding surface.
• Oil film between the spool and body
disappears due to abnormally high oil
temperature.
• Lubrication is improper due to deterio-
rating oil.
• Spool is worn from long use or due to
pressure bearing on one side only.
• Spool is bent from externally applied
pressure.
• Entire valve is strained due to strain in
the installation face.
• Valve was used at a pressure or a flow
volume which was out of specification.
• Bolts used to assemble the valve were
tightened excessively.
• Oil is accumulating in the cover (the
side with a spring or a detent) opposite
the side where the spool operates.
• Overhaul and repair or replace.
• Use some method to lower the oil tem-
perature or if the relief valve is operat-
ing frequently, investigate the cause and
reduce the frequency.
• This could be alleviated by simply
replacing the hydraulic oil, or it could
require an overhaul of the circuit.
• Check the spool
·
s diameter and consider
the necessity of replacement.
• Check the spool
·
s straightness and other
factors, then repair or replace.
• Loosen the installation bolts, then cut the
installation face and edge and check.
• In the case of pressure, check with a
pressure gauge. In the case of flow vol-
ume, check by the actuator
·
s speed of
movement and the capacity.
• Check if the assembly bolts are tight-
ened to the specified torque. If the torque
deviates markedly from the specified
torque, tighten them again.
• The spool is leaking oil, so when the
spool moves, oil leaks from the cover.
After confirming this, replace the seal.
Cylinder drops while
shifting to a lift opera-
tion.
• Foreign matter is biting into the load
check valve seat or large scratches were
made by foreign matter biting into the
valve
·
s seat previously.
• Disassemble and check, then overhaul
or replace.
to compound the trouble. It is therefore desirable to
proceed so that the causes can be eliminated one at
a time.
Содержание TL150
Страница 1: ...TL150 Track Loader BOOK No CT7E901 WORKSHOP MANUAL Serial No 21500004...
Страница 4: ...0 4...
Страница 5: ...I 1 I GENERAL...
Страница 18: ...I 14 GENERAL...
Страница 19: ...II 1 II SPECIFICATIONS...
Страница 44: ...III 1 III MACHINE CONFIGURATION...
Страница 94: ...III 51 MACHINE CONFIGURATION ELECTRICAL SYSTEM ELECTRICAL SYSTEM ELECTRICAL WIRING DIAGRAM...
Страница 122: ...III 79...
Страница 146: ...MACHINE CONFIGURATION III 103...
Страница 147: ...IV 1 IV HYDRAULIC UNITS...
Страница 152: ...IV 6 HYDRAULIC UNITS HST PUMP 1 Plug 2 Plug 3 Plug 4 Screw 5 Seal Nut 6 Plug Pump Assembly 4 4...
Страница 189: ...IV 43 HYDRAULIC UNITS GEAR PUMP INSPECTION AND ADJUSTMENT IV 36 38 TROUBLESHOOTING IV 39...
Страница 230: ...IV 84 HYDRAULIC UNITS PILOT VALVE INSPECTION AND ADJUSTMENT IV 79 TROUBLESHOOTING IV 80...
Страница 254: ...IV 108 HYDRAULIC UNITS CYLINDERS Corrective Jig E MATERIAL STKM13C Unit mm Corrective Jig E A B Arm 90 75 Bucket 90 75...
Страница 261: ...IV 115 HYDRAULIC UNITS TRAVEL MOTOR DISASSEMBLY AND ASSEMBLY Special tools...
Страница 263: ...IV 117 HYDRAULIC UNITS TRAVEL MOTOR...
Страница 282: ...IV 136 HYDRAULIC UNITS TRAVEL MOTOR...
Страница 283: ...V 1 V TROUBLESHOOTING...