HYDRAULIC UNITS
CONTROL VALVE
IV-54
TB53FR
• Check if it isn't just the cylinder’s natu-
ral drop when the cylinder is held. If the
problem is in the cylinder, disassemble
and repair it.
• Replace the spool or replace the valve
block assembly.
• Manually Operated :
Check if there is something interfering
with the link mechanism.
Pilot Operated:
Check the pilot pressure.
• Disassemble and check, then overhaul
or replace.
Symptom
Can’t be held in the spool
neutral position (cylinder
drops).
• Could be mistaken for a great amount of
leakage in the cylinder.
• The gap between the spool and body is
large, so the amount of oil leaking from
the spool is great.
• Spool won’t return completely to the
neutral position.
• Foreign matter is biting into the port
relief valve seat or the anti-cavitation
valve seat and oil is bypassing. Or a seat
is damaged.
Probable Causes
Remedy
• Foreign matter is biting into the relief
valve seat and oil is bypassing. Or the
seat is damaged.
• The relief valve’s adjustment screw is
loose.
• Foreign matter is biting into the port
relief valve seat or the anti-cavitation
valve seat and oil is bypassing. Or a seat
is damaged.
• Spool stroke is not the specified stroke.
• Pump is damaged and no oil is dis-
charged.
• Disassemble and check, then overhaul
or replace.
• Try tightening the adjustment screw. If
it is loose, correct the setting and tighten
the lock nut securely.
• Disassemble and check, then overhaul
or replace.
• Manually Operated:
Check if there is something interfering
with the link mechanism. Check if a pin
or a pin hole in the link connection is
worn.
Pilot Operated:
Check the pilot pressure.
• Check if the pump is abnormal or not. If
the pump is bad, replace it. Check if the
cause of the abnormality is air being
sucked in, deterioration of hydraulic oil
or shafts not centered, etc.
• The load is too heavy.
• Mechanical resistance of connecting
parts is great regardless of the hydraulic
pressure in the operating unit.
• A large piece of foreign matter is trapped
in the circuit or a pipe is bent, causing
great resistance.
• Compare with an object of the specified
weight.
• Check and replenish hydraulic oil, etc.,
modify or repair.
• Find the affected place and repair it.
The load won’t move.
(Pressure won’t increase.)
Load doesn’t move. (Pres-
sure rises.)
Summary of Contents for TB53FR
Page 1: ...0 1 TB53FR...
Page 2: ...0 2 TB53FR...
Page 3: ...0 3 TB53FR...
Page 6: ...0 6 TB53FR...
Page 8: ...0 8 TB53FR...
Page 9: ...I 1 TB53FR I GENERAL...
Page 24: ...GENERAL I 16 TB53FR...
Page 25: ...I 17 TB53FR II SPECIFICATIONS II 1...
Page 53: ...II 29 TB53FR III MACHINE CONFIGURATION III 1...
Page 60: ...MACHINE CONFIGURATION DRIVE SYSTEM III 8 TB53FR...
Page 68: ...MACHINE CONFIGURATION TRAVEL SYSTEM III 16 TB53FR...
Page 74: ...MACHINE CONFIGURATION UPPER FRAME III 22 TB53FR...
Page 80: ...MACHINE CONFIGURATION CONTROL SYSTEM III 28 TB53FR...
Page 86: ...MACHINE CONFIGURATION ATTACHMENTS III 34 TB53FR...
Page 88: ...III 36 TB53FR HYDRAULIC SYSTEM MACHINE CONFIGURATION...
Page 92: ...TB53FR MACHINE CONFIGURATION ELECTRICAL SYSTEM III 40...
Page 94: ...MACHINE CONFIGURATION ELECTRICAL SYSTEM III 42 TB53FR...
Page 110: ...MACHINE CONFIGURATION INTERFERENCE PREVENTION SYSTEM III 58 TB53FR...
Page 111: ...III 59 TB53FR IV HYDRAULIC UNITS IV 1...
Page 144: ...HYDRAULIC UNITS HYDRAULIC PUMP IV 34 TB53FR...
Page 166: ...HYDRAULIC UNITS CONTROL VALVE IV 56 TB53FR...
Page 186: ...HYDRAULIC UNITS PILOT VALVE IV 76 TB53FR INSPECTION AND ADJUSTMENT IV 71 TROUBLESHOOTING IV 72...
Page 267: ...IV 157 TB53FR V TROUBLESHOOTING V 1...
Page 313: ...V 47 TB53FR VI ENGINE...
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