Takeuchi TB215R Workshop Manual

TROUBLESHOOTING
CONTROL VALVE
2
5
CONTROL VALVE 5J0AQ00
Symptoms Major causes Remedies
Spool’s neutral position
cannot be maintained
(cylinder drops)
• There are cases of a large oil leak in-
side the cylinder.
• Check if the cylinder drops spontaneously
when it is held. If the cylinder is faulty, dis-
assemble and repair it.
• Since the clearance between the spool
and the body is too large, oil is leaking
from the clearance.
• Replace the spool and the valve block as-
sembly.
• Spool is not completely back in the neu-
tral position.
• Manual: Check if the link mechanism is in-
terfering with others.
Hydraulic operation: Check the pilot pres-
sure.
• Foreign matter is caught in the seat of
the port relief valve or of the anti-cavita-
tion valve, and thus the oil is bypassing
the section. Or the seat is damaged.
• Disassemble, overhaul or replace.
Load cannot be moved
(pressure cannot be in-
creased)
• Foreign matter is caught in the seat of
the port relief valve, and thus the oil is
bypassing the section. Or the seat is
damaged.
• Disassemble, overhaul or replace.
• Adjuster screw on the relief valve is
loose.
• Screw in the adjuster screw. If loose, set the
adjustment again and fasten with a lock nut.
• Foreign matter is caught in the seat of
the port relief valve or of the anti-cavita-
tion valve, and thus the oil is bypassing
the section. Or the seat is damaged.
• Disassemble, overhaul or replace.
• Spool stroke is out-of-spec. • Manual: Check if the link mechanism is in-
terfering with others. Check if the pin or pin
hole on the linking section is worn out.
• Oil supply from the pump is insufficient,
because the pump is damaged.
• Hydraulic operation: Check the pilot pres-
sure.
Check for any abnormality in the pump.
If the pump is faulty, replace it and find the
cause of the abnormality (e.g., faulty air
sucking or oil degradation).
Load cannot be moved
(pressure is being in-
creased)
• Overloading • Compare with a one with standard load.
• Mechanical resistance of related parts/
devices (unrelated to the hydraulic
pressure of the hydraulic oil) is large.
• Check and add oil, modify or repair the
parts/devices.
• Large resistance is generated, be-
cause the circuit is clogged with large
foreign matter or the piping is bent.
• Repair if the location of clogging or bent is
known.
• Spool stroke is out-of-spec. • Check if the link mechanism is interfering
with others and if the pin or pin hole on the
linking section is worn out.

Takeuchi TB215R Specifications

General

Brand	Takeuchi
Model	TB215R
Category	Excavators
Language	English